Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 1 of 17 PageID# 18845
`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 1 of 17 Page|D# 18845
`
`
`
`
`
`
`EXHIBIT 4
`
`EXHIBIT 4
`
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 2 of 17 PageID# 18846
`Case 1:20-cv-00393-LO-TCB Document 729ml" “MIMI/“mm“ Illmllmlm "Il'l’lmmlleflirml18846
`
`US008661910B2
`
`(12) United States Patent
`(10) Patent No.:
`US 8,661,910 B2
`
`McLaughlin et al.
`(45) Date of Patent:
`Mar. 4, 2014
`
`(54) CAPACITIVE SENSOR
`
`(75)
`
`-
`-
`.
`Inventors. Patrlch L. McLaughlin, Redmond, OR
`(US), lhomas D. Decker, Redmond,
`OR (US)
`
`(73) Assignee:
`
`IPG, LLC, Redmond, OR (US)
`
`(
`
`) Notlce.
`
`Subject to any dlsclalmer, the term ofthls
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1105 days.
`
`(21) Appl.No.: 11555562
`
`(22) Filed'
`
`Jan. 19, 2007
`
`(65)
`
`Prior Publication Data
`
`US 2008/0173303 A1
`
`Jul. 24, 2008
`
`(51)
`
`Int Cl.
`G01L 9/12
`(52) US 0'
`USPC ............................................... 73/718; 73/724
`(58) Field of Classification Search
`None
`
`(200601)
`
`5,865,174 A
`6,213,955 B1
`6,220,244 B1
`6,418,793 B1
`6,427,690 B1
`6,470,885 B1
`6,532,958 B1
`6,575,163 Bl
`6,712,876 B2
`6,910,482 B2
`6,925,884 B2
`6,992,492 B2
`7,013,898 B2
`7,089,938 152
`2002/0038657 A1
`2003/0094047 A1*
`
`2/1999 Klocppcl
`4/2001 Karakasoglu
`4/2001 McLaughlin
`7/2002 Pechoux
`8/2002 McCombs
`10/2002 Blue
`3/2003 Buan
`6/2003 Berthon-Jones
`3/2004 Cao
`6/2005 Bliss
`8/2005 Hegner
`1/2006 Burdick
`3/2006 Rashad
`8/2006 Gale
`4/2002 Yagi
`5/2003 Torkkeli
`
`.......................... 73/716
`
`2006/0118115 A1
`2004/0035422 A1
`2006/0180149 A1
`2008/0000480 A1
`
`6/2006 Cannon
`2/2004 Truitt
`8/2006 Matarasso
`1/2008 Cannon
`
`(Continued)
`
`OTHER PUBLICATIONS
`US Office Action dated Jul. 5, 2012 issued in US. Appl. No.
`12/472,853.
`
`(Continued)
`
`See application file for complete search history.
`
`P”im‘”y Examine” * Andrc Allen
`(74) Attorney, Agent, or Firm 7 Workman Nydegger
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`7/1972 Day
`3,678,296 A
`11/ 1977 Vensel
`4,057,205 A
`10/ 1978 311d, JR ~~~~~~~~~~~~~~~~~~~~~~~~~~~ 73/718
`4,120,206 A *
`21,221,755: 2 * 33:; Eiflrgdt """""""""""""" 73/718
`4,686,975 A
`8/1987 Naiinon
`5,052,400 A
`10/1991 Dietz
`5,062,302 A *
`11/ 1991 Petersen et a1.
`5434386 A
`8/1992 Ball
`2:33:33 2
`$1332 ggeienberger
`5,558,086 A
`9/1996 Smith
`5,603,315 A
`2/1997 Sasso
`5,697,364 A
`12/1997 Chua
`
`................. 73/754
`
`(57)
`
`ABSTRACT
`.
`.
`.
`.
`A capaCltlve sensor for measurlng pressure comprlses a fixed
`charge plate integral to a printed circuit board, a flexible
`charge plate that is grounded, a conductive donut-shaped
`adhesive spacer between the charge plates, a lid, a non-con-
`ductive donut-shaped adhesive spacer between the second
`charge plate and the lid, means of providing a pressure, fixed
`or variable, to both sides of the flexible charge plate, wherein
`a microcontroller controls a power supply and provides a
`voltage to the first charge plate wherein the accumulative
`voltage may be measured as a means of determining differ-
`emlal Pressure
`
`26 Claims, 9 Drawing Sheets
`
`
`
`RJ RE DVA_OO1642744
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 3 of 17 PageID# 18847
`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 3 of 17 Page|D# 18847
`
`US 8,661,910 B2
`
`Page 2
`
`(56)
`
`References Cited
`
`2009/0056708 A1
`
`3/2009 Stenzler
`
`U.S. PATENT DOCUMENTS
`
`OTHER PUBLICATIONS
`
`2008/0035150 A1
`zoos/0053541 A1
`2008/0078392 A1
`2008/0282880 A1
`
`2/2008 Rittner
`3/2008 Meckes
`4/2008 Pelletier
`11/2008 Bliss
`
`Notice of Allowance dated Jan. 18, 2013 issued in US. Appl. No.
`12/472,853.
`
`* cited by examiner
`
`RJ RE DVA_OO1 642745
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 4 of 17 PageID# 18848
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 4 of 17 Page|D# 18848
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 1 of 9
`
`US 8,661,910 B2
`
`J“
`
`A 106
`
`DIGITAL OUTPUT
`1028
` RESISTOR
`
`
`
`
`Microcontrollcr
`102
`
`FIGURE 1a
`
`‘L
`
`A 116a
`
`
`RESISTOR
`
`
`DIGITAL OUTPUT
`
`llZc
`
` 250
`DUAL SENSOR
`
`
`
`|
`113!)
`ll?!) —
`
`RESISTOR
`DIGITAL OUTPUT
`lle
`
`
`
` I
`
`A “6b
`
`’5!)
`
`TEMPERATURE SENSOR
`
`
`
`
`
`INTERFACE
`TRANSCIEVER
`
`LIDUID CRYSTAL
`DISPLAY
`
`KEYPAD
`
`NENon DEVICE
`
`ALERT DEVICE
`
`119
`
`DIGITAL INTERFACE
`
`1129
`
`120
`DIGITAL INTERFACE
`1 12h
`
`
`
`DIGITAL INTERFACE
`llZI
`
`
`DIGITAL INTERFACE
`IIZJ
`
`
`DIGITAL INTERFACE
`l 1 2k
`
`
`
`HICROCONTROLLER
`112
`
`
`
`
`
`
`
`
`
`FIGURE 1b
`
`RJ RE DVA_OO1642746
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 5 of 17 PageID# 18849
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 5 of 17 Page|D# 18849
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 2 of9
`
`US 8,661,910 B2
`
`PLASTIC LID
`ADHESIVE SPACER
`METALIZED MEMBRANE
`CONDUCTIVE ADHESIVE SPACER
`NON-CONDUCTIVE MASK
`COPPER GROUNDING CONTACT
`PRINTED CIRCUIT BOARD
`COPPER SHIELDING PLATE
`COPPER SENSING PLATE
`
`o'o'o'o'o'o'o'o'
`’0?o‘s'o’o‘o’o a
`
`
`
`210
`
`SINGLE CAPACITOR
`FIGURE 2a
`
`COPPER SENSING PLATE 268
`COPPER SHIELDING PLATE 267
`PRINTED CIRCUIT BOARD 266
`COPPER GROUNGING CONTACT
`270
`V////////////}{//////////////////////////////////fl’//////////
`
`CONDUCTIVE ADHESIVE SPACER 251 x,
`NON-CONDUCTIVE MASK 269 X.
`?\\\\\\\\\V
`
`
`METALIZED MEMBRANE
`252 ——>
`
`
`NON-CONDUCTIVE MASK 259
`CONDUCTIVE ADHESIVE SPACER 253
`
`U
`
`
`COPPER GROUNDING CONTACT
`25‘!
`
`
`PRINTED CIRCUIT BOARD 256
`COPPER SHIELDING PLATE 257
`COPPER SENSING PLATE 258
`
`m /
`
`250
`
`DUAL CAPACITOR
`FIGURE 2b
`
`RJ RE DVA_OO1 642747
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 6 of 17 PageID# 18850
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 6 of 17 Page|D# 18850
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 3 of9
`
`US 8,661,910 B2
`
` E
`
`——)> Y = (A/Ds_1 + A/Ds_2 + A/Ds_3 = A/Drs) - 'gain factor'
`
`305 ——/
`
`figure 3a
`
`RJ RE DVA_OO1 642748
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 7 of 17 PageID# 18851
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 7 of 17 Page|D# 18851
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 4 of9
`
`US 8,661,910 B2
`
`MEASURMENT
`CYCLE
`
`
`
`internal
`
`signal
`
`
`
`_
`
`_ _
`
`—— — Vdd
`
`
`
`
`S/D
`pressure
`series of
`functions
`
`SD_A
`
`303b/306b
`
`Vss
`
`E —j> Y = (A/Ds_l + A/Ds_2 + A/Ds_3 = A/Drs) - 'gain factor‘
`
`figure 3b
`
`RJ RE DVA_OO1 642749
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 8 of 17 PageID# 18852
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 8 of 17 Page|D# 18852
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 5 019
`
`US 8,661,910 B2
`
`CONDUCTIVE ADHESIVE SPACER 204
`
`METALIZED MEMBRANE
`
`203
`
`ADHESIVE SPACER 202
`
`PLASTIC LID 20!
`
`7013
`
`701b
`
`.‘
`;
`
`FIGURE 4
`
`RJ RE DVA_OO1 642750
`
`

`

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`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 9 of 17 PageID# 18853
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`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 10 of 17 PageID# 18854
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 10 of 17 PagelD# 18854
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 7 0f9
`
`US 8,661,910 B2
`
`
`
`FIGURE5b-BreathCycleshowingMeasurementCycles
`
`
`
`
`
`
`
`IIIIIII
`
`Il-l‘lllllllllII
`
`lllll
`l-Il-i-l-l-l-I
`I‘llllllllllllll
`Illlllllll
`l.l-l-IIIIII
`
`3.5
`
`3.0
`
`2.5
`
`2.0TimeinSeconds
`
`1.5
`
`1.0
`
`0.0
`
`IIIIIIIIIIIIIIlIIIIIIIII
`
`
`
`
`
`-1,A
`
`
`
`
`
`513:.IIIIIIIlIlIlIlIlIIl
`
`
`
`SIIOA U! afieuon
`
`RJ RE DVA_OO1642752
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 11 of 17 PageID# 18855
`Case 1:20-cv-OO393-LO-TCB Document 729-2 Filed 06/16/21 Page 11 of 17 Page|D# 18855
`
`US. Patent
`
`Mar. 4, 2014
`
`Sheet 8 of 9
`
`US 8,661,910 B2
`
`609
`
`|
`
`|
`
`103
`
`INHALATIONw
`
`AMBIENT
`“”5““ " SW“ —-uxcmcomszoucn
`
`
`7///////////////////////////////////////////////////////////.
`606
`
`206
`PCB
`
`
`
`102
`
`
`V‘ 610
`Ox _gen
`2e “(tery
`Y5 en
`
`33 CANNULA
`ncz msx
`
`FIGURE 6
`
`RJ RE DVA_OO1 642753
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 12 of 17 PageID# 18856
`
`lualud •sil
`
`ttoz 't .-IRIAT
`
`6 Jo 6 WIN
`
`Za 016'199'8 Sfl
`
`—160E-12
`
`—80E-12
`
`—40E-12
`
`—20E-12
`
`—10E-12
`
`60E-6
`
`40E-6
`
`Time in Seconds
`
`20E-6
`
`000E+0
`
`0.0
`
`179L1791.00—VACIHD:i
`
`V
`
`AP
`
`1.0
`
`> 2.0
`
`740
`
`s 3.0
`
`4.0
`
`5.0
`
`FIGURE 7 -- Overlapped Measurement Cycles showing Different
`
`Capacitance Values of the Sensor
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 13 of 17 PageID# 18857
`
`US 8,661,910 B2
`
`CAPACITIVE SENSOR
`
`II. CROSS REFERENCE TO RELATED
`APPLICATION
`
`U.S. Pat. No. 6,220,244, "Conserving device for use in
`oxygen delivery and therapy", McLaughlin, is herein incor-
`porated in its entirety by reference.
`
`III. STATEMENT REGARDING FEDERALLY
`SPONSORED RESEARCH OR DEVELOPMENT
`
`Not Applicable.
`
`IV. REFERENCE TO SEQUENCE LISTING, A
`TABLE, OR A COMPUTER PROGRAM LISTING
`COMPACT DISC APPENDIX
`
`Not Applicable.
`
`V. BACKGROUND OF THE INVENTION
`
`Refer to U.S. Pat. No. 6,220,244, "Conserving device for
`use in oxygen delivery and therapy", McLaughlin.
`
`VI. BRIEF SUMMARY OF THE INVENTION
`
`None included.
`
`VII. DETAILED DESCRIPTION OF THE
`(INFORMAL) DRAWINGS
`
`FIG. la is a schematic diagram illustrating a circuit for
`driving a single capacitor sensor.
`FIG. lb is a schematic diagram illustrating a circuit for
`driving a dual capacitor sensor.
`FIG. 2a is an exploded side view of a single capacitor
`sensor.
`FIG. 2b is an exploded side view of a dual capacitor sensor.
`FIG. 3a is an event timing diagram with a corresponding
`asymptotic accumulation of voltage across a capacitive sen-
`sor and a summation thereof for a given pressure.
`FIG. 3b is an event timing diagram with a corresponding
`asymptotic accumulation of voltage across a capacitive sen-
`sor and a summation thereof for variable pressures.
`FIG. 4 is an exploded view of selected components of a
`single capacitor sensor.
`FIG. 5a is an event timing diagram of a waveform of 2
`respiratory cycles with a bolus of oxygen delivered during the
`second inspiration event.
`FIG. 5b is time-voltage curve of a single respiratory cycle
`derived from the amplitudes calculated from multiple mea-
`surement cycles.
`FIG. 6 is a schematic of an application of the invention in an
`electronic oxygen delivery system.
`FIG. 7 depicts time-voltage curves for a single measure-
`ment cycle representative of various points in a respiratory
`cycle.
`Note: headings provided herein are for convenience and do
`not necessarily affect the scope or interpretation of the inven-
`tion.
`
`VIII. DETAILED DESCRIPTION OF THE
`INVENTION
`
`FIG. 2a depicts a preferred embodiment of the subject
`invention a sensor assembly 210 including a single capaci-
`
`25
`
`2
`tor with at least one sensing plate. Sensor assembly 210 is
`preferably used as the sensing component of a pressure trans-
`ducer. Pressure transducers have many applications which are
`well known in the art and related arts.
`5 FIG. 2a specifically is an exploded, in part, side view of a
`single capacitive, or capacitor, sensor assembly 210 the
`invention may include the following fixedly stacked compo-
`nents: a plastic lid 201; a first adhesive spacer 202; a metal-
`ized membrane 203; a conductive adhesive spacer 204; a
`o copper grounding contact 205; a PCB 206: a copper shielding
`plate 207; a copper sensing plate 208; and a non-conductive
`mask 209.
`FIG. 4 is an exploded perspective view of plastic lid 201;
`adhesive spacer 202, metalized membrane 203, and adhesive
`15 spacer 204 and includes the preferred location of ports 701a
`and 701b in plastic lid 201 when the subject invention is used
`with an oxygen delivery system for general aviation. Ports
`701a and 701b are the ports of the corresponding apertures
`through lid 201 which enable the introduction of a first pres-
`20 sure, ambient or other, into chamber 219a and thereby to top
`side of the metalized membrane 203 when the stacked com-
`ponents are assembled. In this application of the invention the
`ports are preferably tubularly coupled with ambient pressure
`and are approximately 0.125 inches in diameter.
`FIGS. 2a and 2b do not depict apertures 701a or 701b nor
`do they depict means to introduce a second pressure to the
`bottom side of the metalized membrane 203 see chamber
`219b. Aligned aperture through non-conductive mask 209,
`copper sensing plate 208, printed circuit board 206, and cop-
`30 per shielding plate 207 enable the introduction of a second
`pressure to the bottom side of the metalized membrane 203
`via chamber 219b. In this application of the invention the port
`defined by these aligned apertures in copper shielding plate
`207 (again, not shown) is pneumatically coupled with a can-
`35 nula or face mask. Apertures are sized and placed so as to
`evenly and timely introduce pressure changes to chambers
`219a and 219b and thereby metalized membranes 203 and
`252 (see chambers 279a and 279b) and prevent damage to
`metalized membranes 203 and 252 in the event that the pres-
`40 sure, in either chamber (219a or 219b), is so great, or the
`opposite chamber (219b or 219a) negative pressure is so
`great, so as to deflect the membrane 203 or 252 into at least
`one aperture to damage it sufficiently to effect performance—
`e.g. plastic deformation.
`The single capacitor sensor 210 in FIG. 2a is preferably
`used when accurate, precise, and timely pressure measure-
`ments are needed when the metalized membrane 203 deflects
`toward sensing plate 208. Dual capacitor sensor 250 as
`depicted in FIG. 2b would be a preferred alternative embodi-
`50 ment when accuracy, precision, and timeliness are needed
`when metalized membrane 203, or in FIG. 2b metalized
`membrane 252 deflects up or down a true differential pres-
`sure sensor. One means of grounding the components in FIG.
`2b is depicted.
`Regarding the assembly of the single capacitor depicted in
`FIG. 2a, the first adhesive spacer 202 is a means for securely
`fixing the plastic lid 201 to metalized membrane 203 wherein
`the spacer 202 is preferably square with a round aperture and
`the first chamber 219a is defined therein. Preferably first
`60 adhesive spacer 202 is substantially non-conductive. Prefer-
`ably the first chamber 219a is substantially sealed so the
`pressure therein may be controlled and accurately measured.
`The pressure may be a vacuum or preferably (and as
`described herein) the lid may have an aperture or port, or more
`65 than one, which may introduce a pressure the pressure
`source may be regulated or controlled, or alternatively may be
`an unknown and uncontrolled. In the preferred application of
`
`45
`
`55
`
`RJREDVA_001642755
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 14 of 17 PageID# 18858
`
`US 8,661,910 B2
`
`3
`the preferred embodiment of the invention two lid ports 701a
`and 701b are coupled to ambient pressure as part of a supple-
`mental oxygen conserving delivery system for use in general
`aviation. The spacer 202 is preferably substantially non-con-
`ductive so as not to affect the charge on the membrane 203.
`Alternatively the lid may be comprised of a second PCB
`266. PCB 266 (or PCB 206) may originally include a copper
`laminate, or copper laminates, which may be etched to form
`copper sensing plates 268 and 258 (or copper sensing plate
`208), and provide copper shielding plates 257 and 267 (or
`207).
`A second copper sensing plate 268 as illustrated in FIG. 2b
`will enable symmetrical sensing which may be a significant
`improvement for some true differential pressure sensor appli-
`cations. And an additional copper shielding plate 267, which
`may be integral to the second PCB 266, will improve the
`performance of the dual capacitor sensor as preferably
`depicted in FIG. 2b.
`Shielding plates 207, 257 and 267 provide electromagnetic
`shielding so metalized membranes 203 and 252 and copper
`sensing plates 208 and 258 and 268 respectively are electro-
`magnetically isolated so as to improve the performance of the
`capacitive sensors.
`Any of a number of alternative insulating, spacing, and
`securing means well known in the arts could be employed to
`achieve the function of spacer 202. Alternative means of
`defining a chamber 219a are may include a concave cavity
`(chamber) on the underside of lid 201 and alternative means
`for non-conductively securing the lid 201 to the membrane
`203 including any of a number of adhesives well known in the
`art. Alternatively various manufacturing processes could be
`employed wherein these components and their functions
`could be combined into different, fewer or even a single part
`such as a plastic molded top that included the functions of lid
`201 and means to affix to, and insulate from, membrane 203.
`Preferably, the metalized membrane 203 is comprised of a
`flexible aluminized Mylar and is approximately 0.010 inches
`from the surface of the lid and 0.006 inches from non-con-
`ductive mask 209). This distance permits the lid 201 to act as
`a stop when the membrane experiences a significant pressure
`(negative pressure from the first pressure source in chamber
`219a or positive pressure from a second pressure source in
`chamber 219b see below). The stop prevents the membrane
`from experiencing excessive excursion which can be damag-
`ing, such as plastic deformation or premature fatigue from
`repeated excessive pressures/loads.
`Conductive adhesive spacer 204 provides a means of
`grounding the membrane 203 and securing membrane 203 to
`the printed circuit board 206 and thereby defining chamber
`219b.
`As was the case with adhesive spacer 202 preferably adhe-
`sive spacer 204 is square with a round aperture therein, but
`any adequate aperture in the spacers could be equally func-
`tional and while it is preferred the spacers have the same
`dimensions it is not necessary. Alternative means of ground-
`ing the membrane 203 include a separate electrical contact
`between the membrane 203 and ground which is independent
`of the other components in FIG. 2a or wherein membrane 203
`is grounded to copper grounding contact 205 independent of
`conductive adhesive spacer 204. Preferably membrane 203 is
`grounded via spacer 204 to copper grounding contact 205
`(distinct from substantially insulated from copper sensing
`plate 208) on the PCB 206 when assembled (or etched there
`from).
`The metalized membrane 203 is a first charge plate and the
`copper sensing plate 208 is a second charge plate of a capaci-
`tor. As described herein, printed circuit board 206 and sensing
`
`4
`plate 208 preferably have apertures which share an axis such
`that they are coupled to a second pressure source which is
`introduced to chamber 219h. Preferably a non-conductive
`mask 209 may be disposed between the copper sensing plate
`5 208 and the membrane 203 which will keep the metalized
`membrane 203 from shorting in the event it is deflected so as
`to come in contact with copper sensing plate 208.
`An alternative embodiment, which does not conceptually
`depart from the single capacitor sensor depicted in FIG. 2a
`o and described, preferably and alternatively herein, is depicted
`in FIG. 2b. Preferably this alternative embodiment includes
`all the components included in FIG. 2b but it can be appreci-
`ated that depending upon the application one skilled in the art
`could select from the additional components and their func-
`15 tions in FIG. 2b vis-avis FIG. 2a and enable a capacitive
`sensor. For example, the lid 201 in FIG. 2a may be replaced
`with another sensing plate namely, copper sensing plate
`268 and conductive adhesive spacer 251 but may not require
`PCB 266 or copper shielding plate 267 or non-conductive
`20 mask 269.
`Alternatively, lid 201 may simply be replaced with printed
`circuit board 266 if the device needs another board the PCB
`266 could easily provide all the functions as lid 201. The
`non-conductive mask 269 and copper shielding 267 are pre-
`25 ferred if this alternative is a dual capacitor sensor which
`requires a second sensing plate to enable the second capaci-
`tor in this case copper sensing plate 268. The second sens-
`ing plate will provide for two capacitors which is preferred if
`the application is for a symmetrical differential pressure sell-
`30 sor. Obviously, and consistent with the embodiments
`described herein apertures in the conductive mask 269, cop-
`per sensing plate 268, copper shielding plate 267 and printed
`circuit board 266 would be necessary to maintain a port so as
`to introduce a pressure to chamber 279a. Introduction of a
`35 pressure to chamber 279b would be akin to the chambers
`219a and 219b depicted in FIG. 2a.
`Capacitive sensors depicted in FIGS. 2a and 2b are driven
`by the circuits depicted in FIGS. la and lb respectively. FIG.
`la depicts a simple RC circuit 101 which includes control
`40 means preferably a microcontroller 102—any of a number of
`adequate off the shelf controllers are well known in the art
`including Microchip PIC12C672 or PIC16F676. While the
`circuit can be driven any number of ways, for example the rise
`or fall times may vary or the voltage may vary, preferably a
`45 digital output 102a of microcontroller 102 is a pulse of 5 volts
`103 (preferably the rise and fall times are 1 microsecond or
`less), which is applied through resistor 104 of a known
`value—preferably 1 M ohm. The resistor limits the current of
`the applied voltage and may vary based upon principles well-
`50 known in the electronic arts. An impedance buffer, preferably
`an operational amplifier 105, tracks the voltage and applies it
`to the analog-to-digital converter input 102b on the micro-
`controller 102 wherein the means for measuring the accumu-
`lated voltage takes place. The voltage source 103 and resis-
`55 tance 104 are of known values. The accumulated voltage
`across the capacitor for a given amount of time will therefore
`represent the distance between the charge plates in the single
`capacitive sensor 210. The components are calibrated and the
`microcontroller is programmed so the value of the capacitor
`60 varies with the air pressure placed upon it—thereby rendering
`a transducer. Preferably, the device is calibrated such that
`metalized membrane 203 is an initial distance from fixed
`charge plate (copper sensing plate) 208 when the pressures in
`chambers 219a and 219b are equal and deflects based upon
`65 the differential pressure in said chambers. So the pressure put
`upon the flexible charge plate (metalized membrane 203) can
`be calculated (by software or firmware or a functional equiva-
`
`RJ REDVA_001 642756
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 15 of 17 PageID# 18859
`
`US 8,661,910 B2
`
`5
`lent preferably in or downloaded to the microcontroller
`102) from a single pressure source for absolute pressure or
`two pressure sources for differential pressure.
`As depicted in FIG. la nd FIG. 2a, the preferred embodi-
`ment of the invention is not a true differential pressure sensor
`but a sensor for use in an oxygen delivery system wherein
`precise, accurate and timely data on exhalation is not neces-
`sary for desirable oxygen conservation. Deflection of mem-
`brane 203 toward sensing plate 208 preferably occurs during
`inspiration or inhalation and deflection toward lid 201 occurs
`during expiration or exhalation. Accurate, precise and timely
`data enables the timely delivery of a bolus of oxygen. As
`depicted in FIG. 6, the microcontroller output line 602 rep-
`resents the conditioned signal from the sensor 210 for exter-
`nal use in this case signaling valve assembly 605 to open
`valve 608 which enables a bolus of oxygen to be delivered to
`the user.
`To illustrate a function of the RC circuit 101, refer to FIG.
`3a. One measurement cycle starts with raising the voltage at
`SD_R 301 from zero to a known value preferably 5 volts.
`This is followed by measuring the accumulated voltage
`across the capacitor at three points A/Ds_1, A/Ds_2 and
`A/Ds_3 (302a-c) a single measurement cycle. Sigma 305
`represents the addition of these three voltages and may be
`used to approximate the area under curve 303. Multiple mea-
`surements help zero out noise. This is followed with lowering
`the voltage to zero see 306a and 306b for a time period that
`allows the capacitive sensor 210 to discharge to or near zero.
`Another measurement cycle cannot begin until sufficient time
`has elapsed for the capacitor to discharge to near zero. The
`zero point can be calibrated by the microcontroller 102 to a
`baseline if fast repetition rates are necessary. In the most
`preferred embodiment of the subject invention 16 measure-
`ment cycles are made and the values summed and conditioned
`(including averaging to reduce noise and improve the accu-
`racy of the correlation between accumulated voltage and the
`pressure on metalized membrane 203) to create a value that
`closely approximates the area under the asymptotic curve
`303. Other means of measuring the accumulated voltage may
`be employed as long as these values are properly calibrated
`to represent a distance between the metalized membrane 203
`and sensing plate 208 (which is preferably copper) and there-
`fore a pressure. It should be noted that curve 303 may not be
`asymptotic depending upon the circuit characteristics and
`the pulse characteristics the accumulated voltage may be
`linear or some other shape.
`FIG. 3b illustrates a range of rates of accumulated voltage
`based upon the processes described in FIG. 3a see SD_A2
`in FIG. 3b. Each curve represents a different pressure put on
`membrane 203 which will be described in more detail. These
`values may be compared to other calculated values derived
`from the accumulated voltage to either determine a differen-
`tial pressure in a true differential pressure sensor or alterna-
`tively if the capacitive sensor 210 is part of an electronic
`oxygen conserving delivery system (See FIGS. 5a, 5b and 6)
`as a means for tracking respiration to determine the optimal
`bolus of oxygen and the timing thereof
`FIG. 7 depicts time-voltage curves for a single measure-
`ment cycle representative of various points in a respiratory
`cycle exhalation 801, no breathing 802, a small rate of
`inhalation 803, a moderate rate of inhalation 804 and large
`rate of inhalation 805. The x axis is time in seconds (note
`exponent) accordingly 16 measurement cycles may be
`made in a fraction of a second.
`FIG. 5a is an event timing diagram of a waveform of 2
`respiratory cycles with a bolus of oxygen 505 delivered dur-
`
`6
`ing the second inspiration event. Other embodiments of this
`application of the subject invention may deliver gases other
`than oxygen.
`FIG. 5b is time-voltage curve of a single respiratory cycle
`5 derived from the amplitudes calculated from multiple mea-
`surement cycles. FIG. 5b illustrates how the data derived from
`the accumulated voltage in single capacitor sensor 210 and
`described in FIGS. 3a, 3b, and 7 is manipulated to construct
`the waveform representative of respiration or breathing. The
`o accumulated measurements of voltage in FIG. 7 and FIGS. 3a
`and 3b, measured in seconds (note x axis exponent) are aver-
`aged and added to construct the wave form in FIG. 5b wherein
`511 represents a state of no breathing, 512 represents the
`beginning of an inspiration event (510b trip threshold for
`15 breath detection), 513 represents when an inspiration event
`may be confirmed and a bolus of oxygen (preferably) is
`delivered, the area below the baseline (for no breathing) 510a
`and above respiration curve 516 estimates the total volume of
`inspiration, 514 represents expiration and 515 represents no
`20 breathing. Baseline 510a may represent zero pressure per
`calibration of the sensor 210, and may change based upon
`accumulated data from prior respiration events). It should be
`appreciated that other means of mathematical manipulation
`of the data derived from the accumulated voltage across sell-
`25 sor 210, or alternatively 250, may yield the same results if the
`system or device is properly calibrated.
`To elaborate, in FIG. 5a 501a-c indicate zero pressure, that
`is, no inspiration or expiration which means membrane 203 is
`neither trending up or down for which it is calibrated. 502a-b
`30 indicate a negative pressure or inspiration. 503a-b indicate
`positive pressure or expiration. 504 indicates a triggering
`event wherein the microcontroller opens the valve 608 in the
`valve assembly 605 for a calculated time interval to provide a
`bolus 505 to the cannula or face mask. 502b (dotted line)
`35 indicates the inspiration superimposed by the bolus 505 and
`508 indicates the follow-through of that inspiration event.
`The bolus delivered to the inspiration tube 606 may be
`delivered to a delivery device such as a cannula or face mask.
`The bolus will vary depending upon the physical character-
`40 istics of the delivery device used by the patient or pilot. It
`should be appreciated that while the subject invention has
`been described for use in an oxygen delivery system there are
`many other applications, non-medical and medical for which
`it could be utilized. In particular the subject invention could
`45 be utilized in a respiratory monitoring system to detect, mea-
`sure, and report respiratory characteristics based on calcu-
`lated differential air pressures put upon sensor 210 or alter-
`natively 250.
`FIG. lb depicts two simple RC circuits which drive the
`50 dual capacitor sensor 250. Microcontroller 112 serves the
`same functions as microcontroller 102 but drives an addi-
`tional circuit, see digital outputs 112b and 112c and processes
`additional data, see analog inputs 112a and 112d. Other
`devices are depicted in FIG. lb which may enhance the per-
`55 formance of the device such as barometer 117, which may be
`used to determine when a pilot may need supplemental oxy-
`gen among other uses. It is well known in the art of aviation
`that barometers are used to measure pressure altitude. Tem-
`perature sensor 118 may also provide data on ambient tem-
`60 peratures which may be useful in optimizing the performance
`of the device. The interface transceiver 119, LCD 120, keypad
`121, and alert device 123 may facilitate the use and enhance
`the performance of the device. The memory device 112 may
`store respiration and system data to provide a record for later
`65 retrieval which may be used to monitor system performance.
`Regarding microcontroller 112 (or 102) any of a number of
`adequate off the shelf controllers are well known in the art
`
`RJREDVA_001642757
`
`

`

`Case 1:20-cv-00393-LO-TCB Document 729-2 Filed 06/16/21 Page 16 of 17 PageID# 18860
`
`US 8,661,910 B2
`
`7
`would suffice including Microchip PIC12C672 or
`PIC1617676. While the circuits depicted in FIGS. la and lb
`may be driven any number of ways that are well known to
`those skilled in the art, the preferable means of driving the
`circuits in the dual capacitor sensor 250, see digital outputs
`112c and 112b, is a 5 volt pulse 113a and 113b respectively,
`which is alternately applied through resistors 114a and 114b
`respectively, which are of a known value preferably 1 M
`ohm. The resistor limits the current of the applied voltage and
`may vary based upon principles well-known in the electronic
`arts. Impedance buffers, preferably an operational amplifier
`115a and 115b, tracks the voltage and applies it to the analog-
`to-digital converter inputs 112a and 112d on the microcon-
`troller 112 wherein the means for measuring the accumulated
`voltages takes place. The voltage sources and resistances are
`of known values. The accumulated voltage across the capaci-
`tor for a given amount of time will therefore represent the
`position of metalized membrane 252 in dual capacitive sensor
`250. The components are calibrated so the value of the capaci-
`tor varies with the net air pressure (see chambers 279a and
`279b) placed upon metalized membrane 252, so the pressure
`put thereon can be calculated (by software or firmware or a
`functional equivalent preferably in or downloaded to the
`microcontroller 112)—the accuracy and precision of the dual
`capacitor sensor 250 is preferably symmetric.
`FIG. 6 is a schematic of an oxygen delivery system 601
`which conserves oxygen an implementation of the subject
`invention. The inspiration sensor 210 resides on the PCB 206.
`The microcontroller 102 controls the power source 603 to
`provide a voltage 103 to a charge plate (either the flexible
`metalized membrane 203 or the fixed copper sensing plate
`208 but preferably the sensing plate 208) in inspiration sensor
`210. When an inspiration event is detected the microcontrol-
`ler 102 sends an output signal 604 to the valve assembly 605
`which opens valve 608 and a bolus 505 is delivered to inspi-
`ration tube 606. The power source 603 may s