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`USOOSS 1700816.
`
`United States Patent
`Rafert et al.
`
`[19]
`
`[11] Patent Number:
`
`5,817,008
`
`[451 Date of Patent:
`
`Oct. 6, 1998
`
`[54] CONFORMAL PULSE OXIMETRY SENSOR
`AND MONITOR
`
`['75]
`
`Inventors: Stephen C. Rafert, Kent; David R.
`Marble. Seattle. both of Wash: Glenn
`W. Pelikan, Portland, Greg; Alan
`Kahn, Minneapolis, Minn.
`
`[73| Assignee: Spaeelnhs Medical, lne., Redmond,
`Wash.
`
`[21] App}. 116.: 741,135
`
`[22]
`
`1-1166:
`
`Oct. 31,1996
`
`
` [51] Int. c1? ............. .. A61]! 5700
`
`61107323; 6007344
`[52] use].
`[58]
`Field of Search
`[BS/633,664,
`1287665, 666; 356741; 6007310, 322, 323,
`340. 344. 473. 476
`
`[56]
`
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`.. 1287633
`ilaniaguri
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`1611615 ..
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`1271981 Reissmucllc c
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`1287640
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`1071982 Ayer
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`271983 Carlmcl! ..
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`471983 Jobsis cl :1.
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`971983 Wesseling et a].
`1287633
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`FOREIGN PM'EN'I‘ DOCUMENTS
`
`671279
`0 019 478
`2 039 364
`
`107l963 Canada .
`1171980
`European Pet. 00'. .
`871980 United Kingdom .
`
`Primary Examiner—Jennifer Bahr
`Assistant Exmm'rrer—Eric F. Winakur
`Attorney, Agent, or Firm~Seed and Berry LLI’
`
`[57]
`
`ABSTRACT
`
`Art optoelectronic pulse oximctry sensor is described which
`physically conforms to a body portion of a patient, such as
`a linger, and provides a lirm pressing engagement between
`the sensor and the patient's body portion. The sensor
`includes a flexible substrate, such as an elastic bandage-type
`materiai, which is physically conformable and attachable/
`adhcrable to the patient’s body portion. The sensor also
`includes a light source assembly for transilluminaling the
`patient’s body portion, and a light detector assembly for
`measuring transmilted light. The dimensions of the light
`source and light detector assemblies are constructed to
`provide a high aspect ratio relative to the flexible substrate.
`When the sensor is conformabiy applied to the patient’s
`body portion,
`localized pressure is exerted on the body
`portion at the points of contact with the light source and light
`detector assemblies,
`thereby stressing the skin and the
`underlying blood-perfused tissue. The stress imparted to the
`skin and underlying tissues affects the distributions of blood
`in the tissues and provides improved accuracy and sensitiv-
`ity in arterial oxygen saturation measurement, especially in
`circumstances of low perfusion.
`
`40 Claims, 3 Drawing Sheets
`
`20
`
`
`471955 Wood
`2.706.927
`2507239
`171965 Richter
`3,167,653
`. 12872.06
`3.170.459
`271965 Phipps et al.
`871971 Gordy
`12872.06 R
`3,599.629
`871971 Howell et :11
`12872.05 F
`3,602,213
`271972 Show .... ..
`12872 R
`3,638,640
`3.698382 1071972 Howell
`I 2872 Il
`12872 R
`1704,7013
`12.71972
`l-lerczfeld at al.
`3,769,974
`1171973 Smart el :1].
`12872.05 1’
`3.799.672
`371974 Vurek
`356741
`3,807,388
`471974 Orr et al.
`1287205 R
`3,847,483
`1171974 Shaw et al.
`......... 356.741
`3,943,918
`371976 Lewis
`12872.1A
`3.980.075
`971976 ileule
`12872.15 R
`3.998550
`1271976 Konishi el al.
`356739
`4,013,067
`371977 Kresse et al.
`12872.05 R
`4,033,976
`871977 Hardy et :11,
`12872.05 P
`4.052.977
`1071977 Kay
`12872 V
`4,136,915
`571.978 Kofsky et al
`12872 1..
`4,091,803
`571978 Finder
`12872.05 P
`4,109,643
`8.9978 Bond el al.
`12872 I.
`4.121.573
`1071978 Crovella et :11.
`12372.] A
`4.167.331
`971979 Nielsen ..
`.. 356739
`4,223,680
`971980 Jobsis
`1287633
`
`
`
`
`
`..
`
`
`
`0001
`000‘
`
`Apple Inc.
`Apple Inc.
`APL1013
`APL1013
`U.S. Patent No. 8,929,965
`US. Patent No. 8,929,965
`FITBIT, EX. 1013
`
`FITBIT, Ex. 1013
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`5,817,008
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`Page 2
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`...................... 1287065
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`350741
`._ 1287633
`1287637.
`'
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`‘2’”“33
`n 1561634
`1287633
`l237'633
`..
`-- 1287633
`1237033
`. 1287633
`
`
`
`
`
`
`
`us. PATENT DOCUMENTS
`
`
`“was 3.3”.“ “3"
`4394155”
`4"1985 mm“ a]'
`4910-938
`1171986 New, 11. et al.
`4,621,643
`371987 New, 17. e1 :11.
`4.051498
`871937 Goldbergcr cl £11.
`4,685,464
`4,700,708 1071937 New, JL In R], m
`4,726’332
`2171988 Bochmer elm"
`4,759,309
`771983 Taylor
`4,770,179
`971983 New, Jr. cl al.
`4,825,879
`571989 Tan elal.
`.
`
`
`
`
`
`'
`
`‘28’664
`12%”
`1287633
`1287033
`1287633
`N 1287633
`1387567
`. 1287633
`1287033
`1287633
`
`'
`
`571989 Goodman e1 :1].
`4,830,014
`871989 Taylor cl :11.
`4,359,057
`971089 Rich e1 3|.
`4,865,038
`49734403 1071000 Rink :1 :11
`j j
`:3‘039‘243 W991 MP1 W
`330411187
`3/1991 Hm" 9‘ “';
`3,069,213 1211991 Polczynskl “Hum...”
`5,099,842
`371992 Mannheimcr ct :11.
`1
`5,237,994
`871993 ledberger 1-
`5.335.059
`871904 Pologe
`5,427,003
`071995 Ogawa et a].
`
`0002
`0002
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`FITBIT, EX. 1013
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`

`

`U.S. Patent
`
`Oct. 6, 1998
`
`Sheet 1 of3
`
`5,817,008
`
`
`
`0003
`0003
`
`FITBIT, EX. 1013
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`FITBIT, Ex. 1013
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`

`

`U.S. Patent
`
`Oct. 6, 1998
`
`Sheet 2 of 3
`
`5,817,008
`
`
`
`0004
`0004
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`FITBIT, EX. 1013
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`FITBIT, Ex. 1013
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`

`

`US. Patent
`
`Oct. 6, 1998
`
`Sheet 3 of 3
`
`5,817,008
`
`
`
`0005
`0005
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`FITBIT, EX. 1013
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`FITBIT, Ex. 1013
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`

`

`5,817,008
`
`1
`CONFORMAL PULSE OXIMETRY SENSOR
`AND MONITOR
`TECHNICAL FIELD
`
`The present invention relates generally to pulse oximetry
`instruments, and more particularly,
`to an optoelectronic
`pulse oximetry sensor which is physically conformable to a
`body portion of a patient.
`BACKGROUND OF THE INVENTION
`
`it]
`
`15
`
`Oximeters are well known in the art, and are used to
`measure the level of oxygen in a patient's blood non-
`invasively. More precisely, oximeters measure the level of
`anerial oxygen saturation, which is the ratio of arterial blood
`oxyhemoglobin concentration to total hemoglobin concen-
`tration. Optoelectronic pulse oximcters are well known in
`the art and typically include a sensor having a light source,
`such as a light-emitting diode (LED), and a light sensor,
`such as a photodetector. The light sourco emits light which
`transilluminates—that
`is, shines through—the patient's
`body portion, and light which is neither absorbed nor
`scattered away by the blood-perfused tissue is measured by
`the light sensor.
`Although broadaspectrum visual light may be employed,
`more typically light of two or more discrete wavelengths, _
`such as red and infrared wavelengths, is used. The red light
`is primarily absorbed by the oxyhemoglohin, whereas the
`infrared light is primarily absorbed by all blood hemoglobin,
`independent of the oxyhemoglobin concentration. The
`absorption of the red and infrared light
`then varies as a
`function of the quantity of hemoglobin and the quantity of
`oxyhemoglobin in the lightpaths. Both the quantity of hemo-
`globin and the quantity of oxyhemoglobin vary as a function
`of the heartbeat cycle—namely, with the pulsatile distention
`of the arteries.
`the light sensor also
`The amount of light received at
`depends on effects other than light absorption by blood
`hemoglobin, such as
`the effects due to bone, skin
`pigmentation, etc. However, these other elIeets do not vary
`as a function of the heartbeat cycle. Also, the light absorbing
`effects due to venous blood hemoglobin do not vary with the
`heartbeat cycle nearly as much as the effects due to arterial
`blood hemoglobin, since the capillary bed essentially iso—
`lates the veins from the high blood pressure pulse. Thus, the
`light received by the light sensor has both an alternating
`component (associated primarily with the arterial blood
`hemoglobin) and a steady-state component (assoeiated with
`other light absorbing and/or scattering effects of the patient's
`body portion). As is well known in the art, determining the
`ratios of the alternating components to the steady-state
`components allows an accurate determination of arterial
`oxygen saturation. independent of the light absorbing anchor
`scattering effects associated with the steady—state compo-
`nent.
`
`3f]
`
`35
`
`40
`
`45
`
`50
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`2
`The effect of a patient's blood oxygen content on the
`intensity of transmitted light is well known, and is described
`in US. Pat. Nos. 4,621,643. 4,653,498, 4,685,464, and
`4,700,708, which are incorporated herein by reference.Also
`well known in the art are pulse oximetry sensors that are
`placed on the patient’s body portion and substantially physi-
`cally conformed to that body portion. One example is US.
`Pat. No. 4,830,014 to Goodman et al., incorporated herein
`by reference. The sensor described in Goodman et
`a1.
`includes an elongated flexible strip (much like an elastic
`bandage} to which an LED and a photodetector are attached.
`The LED and photodetectol' have a very small physical
`profile. The LED and photodetector are essentially inte
`grated within the flexible strip so that they do not stress the
`skin by imparting localized pressure to the skin beneath the
`LED and light detector. The sensor described in Goodman ct
`al. readily Conforms to the body portion, such as a finger, on
`which it is placed or wrapped.
`The sensor described in Goodman et al. exhibits a number
`of disadvantages. In particular, the sensor would not work
`well unless firmly applied to the patient, and even then
`would provide a measured pulse amplitude which may be
`insufficient for accurate measurement of a patient‘s pulse
`and blood oxygen level. In particular,
`the primary goal
`taught by Goodman et al., i.e., avoiding the application of
`localized stress to the skin (and hence stress.
`to blind-
`perfused tissue beneath the skin), actually impairs the ability
`of the sensor to provide accurate blood oxygen levels.
`SUMMARY OF THE INVENTION
`
`invention, an improved
`in accordance with the present
`optoelectronic pulse oximetry sensor is provided which
`substantially physically conforms to a body portion of a
`patient. The sensor is removably securablc to the patient’s
`body portion by an adhesive coating, and includes at least
`one light source for transilluminating the body portion and
`a light detector for measuring light transmitted through the
`body portion. The sensor includes a flexible substrate having
`an inner surface and an outer surfacefithe inner surface
`disposed towards the body portion and the outer surface
`dISpElSCd away from the body portion. The light source and
`the light detector are mounted on the flexible substrate at
`spaced-apart locations. Significantly, the light source and the
`light detector project a substantial distance from the inner
`surface to provide firm localized pressure against the body
`portion, thereby stressing blood-perfused tissues beneath the
`skin.
`
`In one embodiment, the light source and light detector are
`each enclosed in a substantially rigid transparent housing.
`Each of the housings includes a flange portion securable
`between an inner layer and an outer layer forming the
`flexible substrate. In another embodiment, each of the light
`source and light detector includes a substantially rigid circuit
`board for holding a light source or a light detector and
`providing electrical connections thereto. A substantially
`elastomeric transparent cover is connected to the circuit
`board and covers the corresponding light source or light
`detector.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`is an isometric view of an optoelectronic pulse
`FIG. 1
`oximctry sensor having a flexible substrate, a light source
`assembly, and a light detector assembly according to the
`present invention.
`FIG. 2 is an enlarged cross-sectional view ofthe sensor of
`FIG. 1, showing certain details of a preferred embodiment of
`the light source and light detector assemblies.
`
`Typically, the amplitude of the alternating component is
`of the order of 2%73% of the total light received by the light
`sensor. In circumstances of low perfusion, such as when the
`patient’s body portion is particularly cold, or when a patient
`is in shock. experiencing declining blood pressure, etc., the
`amplitude of the alternating component can be of the order
`of only 1% of the total light received by the light sensor.
`Thus. any signal noise andfor other spurious efi‘ecting tend-
`ing to mimic the alternating component can detrimentally
`affect measurement accuracy. Accordingly, cu rrently avail-
`able oximeters include hardware circuitry and a variety of
`signal processing software algorithms for performing noise
`reduction and other signal processing.
`
`55
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`5,817,008
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`3
`FIG. 3 is an isometric view of the sensor of FIG. 1, having
`the light source and light detector assemblies of FIG. 2,
`showing a portion of the flexible substrate pulled back to
`expose certain details of the inner construction.
`FIG. 4 is an enlarged cross-sectional view ofthe sensor of
`FIG. 1, showing an alternate embodiment of the light source
`and light detector assemblies.
`FIG. 5 is an isometric view showing the sensor of FIG. 1
`connected to a conventional pulse oximetry monitor.
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`An improved pulse oximetry sensor is described which
`substantially physically conforms to a body portion of a
`patient, such as a finger, while providing sufficient stress to
`the patient’s body portion to afiord greater accuracy of
`measurement. In the following description, certain specific
`details are set forth in order to provide a thorough under-
`standing of the preferred embodiment of the present inven-
`tion. However, it will be obvious, to one skilled in the art,
`that the present invention may be practiced without these
`details. In other instances, well—known pulse oxirnetry sen—
`sor components are not discussed in detail in order not to
`unnecessarily obscure the invention.
`FIG. 1 shows a preferred embodiment of an optoelec-
`tronic pulse oximetry sensor 10 made in accordance with the
`present invention. The sensor 10 includes a flexible substrate
`12, such as an elastic bandage-type material. The flexible
`substrate 12 is preferably constructed from a plurality of
`layers which are bonded or otherwise connected to one
`another. The flexible substrate 12 includes an inner surface
`14 and an outer surface 16. The designations of "inner" and
`“outer” correspond with the intended orientation of the
`flexible substrate 12 upon physical conformation with the
`patient’s body portion. The flexible substrate 12 preferably
`includes a conventional adhesive on the inner surface 14 to
`securely attach and conform the sensor 10 to the patient’s
`body portion. Alternatively. if the ends of the substrate 12
`Overlap, a hook-and-loop type fastener of the type corri-
`monly sold under the trademarl-t Velcro® may be suitably
`employed.
`A light source assembly 18 and a light detector assembly
`20 are attached to the flexible substrate 12. The dimensions
`of the light source assembly 18 and light detector assembly
`20 are constructed to provide a high aspect ratio relative to
`the flexible substrate 12. In this way, the light source and
`light detector assemblies 18, 21! project a substantial dis-
`tance from the inner surface [4 of the llexible substrate 12.
`When the inner surface of the flexible substrate 12 is placed
`against
`the skin of the patient’s body portion,
`the light
`source and detector assemblies 18, 20 firmly press into the
`skin to apply substantial stress to the skirt and the blood-
`pcrfused tissue beneath the skin. Consequently, the skin and
`the underlying tissue are displaced and deformed, thereby
`partially depleting the tissue of blood. Poi shown in the
`embodiments depicted in FIGS. 2 and 4, the source and
`detector assemblies 18, 20 project from the flexible substrate
`12 a distance that is not less than approximately the distance
`they extend along the substrate—Le. having an aspect ratio
`relative to the flexible substrate of not
`less than approxiA
`mater 1:1.
`the light
`As in conventional pulse oximctry sensors,
`source assembly 18 may include two light-emitting diodes
`(IJEDsJ emitting light at red and infrared wavelengths, and
`the light detector assembly 20 may include a corresponding
`two or more photodetectors, although a single light detector
`
`5
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`ill
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`is normally used to detect light at both wavelengths. Electric
`signals are carried to and from the light source and light
`detector assemblies [8. 20 by a multistrartd electric cable 22,
`which terminates at an electrical connector 24 to which
`conventional optoelectronic oximeter control and processing
`circuitry is attached.
`The high aspect ratio of the light source and light detector
`assemblies 18, 20 provides a number of distinct advantages
`over prior art pulse oximetry sensors. Some conventional
`pulse oximetry sensors, including sensors like that described
`in Goodman et 31., do not apply pressure to the patient's
`body portion at the points of contact with the light source
`and/or light detector to achieve optimum performance. As
`mentioned above, when the sensor 10 is placer] in substantial
`physical conformance with the patient’s body portion, the
`light source and light detector assemblies 18, 20 each project
`a substantial distance from the inner surface 14 of the
`flexible substrate 12 into lirrn pressing engagement with the
`patient’s body portion.
`the points of contact, localized
`By exerting pressure at
`stress is imparted to blood-perfused tissue beneath the light
`source and detector assemblies 18, 20. This localized stress
`forces some of the blood from the blood—perfused tissues
`adjoining the points of contact. Because a patient’s arterial
`blood is at a higher pressure than the venous blood, a greater
`quantity of venous blood will be removed. This removal of
`venous blood correspondingly decreases associated light
`attenuation effects and thereby increases the amount of light
`reaching the light detector assembly 20, from which the
`measurements of arterial blood oxygen saturation levels are
`determiner]. Also. because the venous blood has been largely
`depleted from the transilluminatcd body portion, any local-
`ized pulse cheers in the veins (due to pulsatile distention of
`adjacent arteries) is minimized. This is particularly advan—
`tageous since arterial oxygen saturation is of primary clini-
`cal
`interest. When the patient’s heart beats,
`there is a
`momentary increase in the arterial pressure and a cone
`sponding increase in arterial blood quantity, thereby causing
`a momentary decrease in the amount of light received at the
`light detector assembly 20, from which the patient’s pulse is
`determined.
`The localized pressure exerted by the light source and
`detector assemblies 18, 20 partially depletes the tissue
`portions adjacent to the assemblies of blood. These tissue
`portions then become more and less depleted of blood as a
`function of the heartbeat cycle, thereby enhancing the alter-
`nating component of the light received at the light detector
`assembly 20. Also, a boundary region separating the blood-
`depleted tissue portions from the surrounding blood-
`perFused tissue portions changes position as a function of the
`heartbeat cycle and creates a shutter-like effect, which
`further enhances the alternating component of the light
`received at
`the light detector assembly 20. line enhanced
`amplitude of the alternating component provided by the
`sensor 10 all‘ords improved reliability, accuracy, and sensi-
`tivity in arterial oxygen saturation measurement.
`'Ihis is
`especially advantageous when arteries are constricted, as
`when dealing with low perfusion slates.
`FIG. 2 shows a Crosspsection of the sean 10 of FIG. 1,
`and depicts a preferred embodiment of the light source and
`light detector assemblies 13,20. Each ofthe light source and
`light detector assemblies 18, 20 includes a rigid transparent
`housing 26, 28, respectively, enclosing other components of
`the light source and light detector assemblies. the transpar-
`ent housings 26, 28 then provide the firm pressing engage-
`rrtent between the light source and light detector assemblies
`18, 20 and the patient’s body portion. The light source
`
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`5,817,008
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`5
`assembly 18 includes a plurality of light sources, such as a
`red LED 30 and an infrared LED 32. The LEDs 3|], 32 are
`mounted on a substantially rigid LED holder 34, which
`preferably includes a printed circuit board for making the
`appropriate electrical connections. The LEDs 30, 32 may be
`encased by a protective covering material 36, such as
`silicone. although the transparent housing 26 itself can
`provide suflicient protection, The light detector assembly 2|]
`includes a single photodetector 38 operable to detect light
`received from the red LED 30 and the infrared LED 32. The
`photodetcctor 38 is mounted on a substantially rigid photo-
`detcetor holder 42, which preferably includes a printed
`circuit board for making the appropriate electrical connec-
`tions. The photodeteclor 38 may be encased by protective
`covering 44, such as silicone, although the transparent
`housing 28 itself can provide suflicient protection.
`Each of the transparent housings 26, 28 includes a flange
`portion 46, 48, respect ively, which extends between an inner
`layer 50 and an outer layer 52 of the flexible substrate 12.
`The llange portions 46, 48 are held between the inner and
`outer layers 50. 52 to secure the light source and light
`detector assemblies 18, 20 to the flexible substrate 12. The
`inner layer 5|] includes first and secoan openings 54, 56
`through which a cover portion 58, 60 of the transparent
`housings 26, 28 extend, all respectively. The cover portions
`58, 6d are preferably rounded so as to minimize any shearing
`effects when applied to a patient’s skin. This shape also
`provides a smooth boundary transition from the blood-
`depleted tissue portions to the surrounding blood-perfused
`tissue portions. which enhances the mobility of the boundary
`region in response to the heartbeat cycle. Correspondingly,
`this enhances the amplitude of the alternating component of
`the light receivad at the light detector assembly 20. Also held
`between the inner and outer layers 50, 52 are the various
`electric wires 62, 64 connecting to the light source and light
`detector assemblies 18, 2!), respectively. The electric wires
`62. 64 are gathered together at the multistrand electric cable
`22, which then emerges from the flexible substrate 12 at a
`position approximater midway between the light source
`and light detector assemblies 18, 2|] (see also FIG. 1).
`FIG. 3 shows a portion of the inner layer 50 pulled away
`to show how the light source and light detector assemblies
`18. 20 are secu red to the flexible substrate 12. In particular,
`the opening 54 in the inner layer 50 is placed over the cover
`portion 58 of the transparent housing 26 of the light source
`assembly 18. The inner and outer layers 50, 52. when
`bonded or otherwise attached, then hold in place the trans-
`parent housing 26 by virtue of the Ilange portion 46 held
`securely therebetween. Also shown is the routing ol'electric
`wires 62, 64 and the electric cable 22.
`FIG. 4 is a cross-sectional view like that of FIG. 2, but
`showing an alternate embodiment of the light source and
`light detector assemblies 18, 20.
`In this alternate
`embodiment,
`the flexible substrate 12 may be suitably
`constructed from a single layer, or from two layers carrying
`the electric wires 62, 64 and a portion of the electric cable
`22 therebetweerl. If the flexible substrate 12 is of a single
`layer construction. the electric wires 62, 64 would preferably
`pass through the flexible substrate 12 and be gathered
`together at the electric cable 22 proximate to (or attached to)
`the outer surface 16 of the flexible substrate 12.
`The light source assembly 18 includes a flexible support
`pad 66, such as a soft foam pad. which is bonded by glue or
`other suitable means to the inner surface 14 of the flexible
`substrate 12. A substantially rigid LED holder, such as a
`printed circuit board 68, is mounted on the support pad 66.
`The printed circuit board 68 provides the appropriate elec-
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`trical connections between the electric wires 62 and the
`LEDS 30, 32 which are mounted on the printed circuit board.
`The electric wires 62 preferably pass from the printed circuit
`board 68 through the flexible support pad 66. The [EDS 30,
`32 are mounted on the printed circuit board 68 and enclosed
`by a rounded soft protective cover, such as a silioone cap 70.
`When the sensor 10 is placed in physical conformance with
`the patient’s body portion, the silicone cap TI] is pressed into
`lirrn engagement with the patient’s body portion to exert
`localized pressure thereon. This localized pressure stresses
`the skin, and hence the underlying blood-perfused tissues,
`and the consequent compression of the skin and underlying
`tissue partially depletes the underlying tissue of blood.
`The light detector assembly 20 is similarly constructed. A
`flexible support pad 72, such as a soft foam part, is attached
`to the inner surface 14 of the flexible substrate 12. The
`electric wires 64 pass through the support pad 72 and
`connect to a substantially rigid photodetector holder, such as
`a printed circuit board 74. The printed circuit board 74
`provides the appropriate electrical connections to the pho-
`todetector38 which is mounted on the printed circuit board.
`The photodetector 38 is enclosed by a rounded protective
`cover, such as a silicone cap 76, which exerts localized
`pressure on the patient’s body portion when the sensor 10 is
`placed in physical conformance therewith.
`The sensor 10 of FIG. 1 is shown in FIG. 5 connected to
`a conventional pulse oxirnetry monitor 80. As is well known
`in the art, the monitor 8|] is bouts-3d in a case 82 and has
`conventional internal circuitrytnot shown) to provide appro-
`priate drive signals to the LEDs 30, 32 (see FIGS. 2 and 4)
`through a connector 84. The case 82 also houses conven-
`tional circuitry (not shown) for receiving the output signal of
`the photorleteetor 38 [see FIGS. 2 and 4) via the connector
`84 and for determining the percentage of oxygen saturation
`in blood-perfused tissues in a body part to which the sensor
`10 is attached. The circuitry then displays the oxygen
`saturation percent in a display window 86 in a conventional
`manner.
`
`it will be appreciated that, although the various embodi-
`ments of the invention have been described above for
`purposes of illustration, a number of modifications may be
`made without deviating from the spirit and scope of the
`invention. For example, the light source and light detector
`assemblies 18, 20 may be constructed in any of a wide
`variety of ways and in a variety of shapes, but all having a
`high aspect ratio relative to the flexible substrate 12 suffi-
`cient
`to provide the attendant
`localized pressure on a
`patient’s body portion to achieve the advantages described
`above. Those skilled in the art will understand that
`the
`advantages described above may be obtained by adapting
`only one ofthc light source and light detector assemblies 18,
`20 to provide the requisite localized pressure on the patient’s
`body portion. Additionally, any of a wide variety of suitable
`means may be employed for attaching andfor adhering the
`flexible substrate 12 to the patient’s body portion. Similarly,
`any ofa wide variety of means for securing the light source
`and light detector assemblies 18, 2D to the flexible substrate
`12 may be employed. Indeed, numerous variations are well
`within the scope of this invention. Accordingly, the inven-
`tion is not limited except as by the appended claims.
`We claim:
`1. An optoelectronic sensor removany securahlc to a
`body portion of a patient, comprising:
`an elastic substrate having an inner surface for disposition
`towards the body portion and an outer surface for
`disposition away from the body portion;
`a light source assembly mounted on the elastic substrate;
`and
`
`0008
`0008
`
`FITBIT, EX. 1013
`
`FITBIT, Ex. 1013
`
`

`

`5,817,008
`
`ill
`
`7
`a light detector assembly mounted on the elastic substrate;
`wherein at least one ofthe light secret: and light detector
`assemblies projects away from the inner surface of the
`elastic substrate. and wherein the elastic substrate is
`adapted to press the one of the light Source and light
`detector assemblies into firm pressing engagement with
`the body portion to exert a localized pressure thereon.
`2. The sensor of claim 1 wherein the light source assembly
`comprises a light source and a substantially rigid transparent
`housing enclosing the light source.
`3. The sensor of claim 2 wherein the substrate comprises
`inner and outer substrate layers. and wherein the transparent
`housing comprises a hollow body portion having a trans-
`parent cover portion at one end and a flange at the other end,
`the flange being positioned between the inner and outer
`substrate layers with the cover portion projecting through a
`hole in the inner substrate layer.
`4. The sensor of claim 1 wherein the light detector
`assembly comprises a light detector and a substantially rigid
`transparent housing enclosing the light detector.
`5. The sensor of claim 4 wherein the substrate comprises
`inner and outer substrate layers, and wherein the transparent
`housing comprises a hollow body portion having a trans-
`parent cover portion at one end and a fia nge at the other end.
`the flange being positioned between the inner and outer -
`substrate layers with the cover portion projecting through a
`hole in the inner substrate layer.
`6. The sensor of claim 1 wherein the light SUUICC assembly
`comprises:
`a light source;
`a substantially rigid circuit board for holding the light
`source and providing electrical connections thereto;
`and
`
`30
`
`a substantially elaslomeric transparent cover connected to _
`the circuit board and covering the light source.
`7. The sensor of claim 6 wherein the light source assembly
`further includes an elastomcric layer attached to the flexible
`substrate on a first side and attached to the circuit board on
`a second side.
`8. The sensor of claim 1 wherein the light detector
`assembly comprises:
`a light detector;
`a substantially rigid circuit board for holding the light
`detector and providing electrical connections thereto;
`and
`
`40
`
`a substantially elastomer‘ic transparent cover connected to
`the circuit board and covering the light detector.
`9. The sensor of claim 8 wherein the light detector
`assembly further includes an elastomeric layer attached to
`the elastic substrate on a first side and attached to the circuit
`board on a second side.
`10. The sensor of claim 1 wherein the elastic substrate
`includes:
`
`an outer layer providing the outer surface;
`an inner layer attached to the outer layer and providing the
`inner surface, the inner layer having an opening; and
`wherein the light source assembly is attached to the elastic
`substrate at a location between the inner and outer
`layers and extends through the opening in the inner
`layer.
`11. The sensor of claim 10 wherein the light source
`assembly includes a substantially rigid transparent housing
`enclosing the light source and having a flange portion and a
`cover portion,
`the flange portion being held between the
`outer and inner layers to attach the light source assembly to
`
`60
`
`65
`
`8
`the elastic substrate. and the cover portion projecting
`through the opening in the inner layer.
`12. The Sensor of claim [It wherein a plurality ofelectric
`wires carrying electric signals to and from the light source
`and light detector assemblies are partly held between the
`outer and inner layers.
`13. An optoelectronic sensor removany securablc to a
`body portion of a patient and having a light source for
`transilluminating the body portion and a light detector for
`measuring transmitted light, the sensor comprising:
`a flexible substrate having an inner surface for disposition
`towards the body portion and an outer surface for
`disposition away from the body portion.
`the flexible
`substrate providing a substantially uniform pressure on
`the body portion;
`a light source amembly connected to the flexible substrate
`and projecting from the inner surface a distance that is
`not
`less than approximately a distance that the light
`source assembly extends along the inner surface, the
`light source assembly thereby adapted to exert a lirst
`localized pressure against the body portion beneath the
`light source assembly to stress skin beneath the light
`source assembly; and
`a light detector assembly connected to the flexible sub-
`strate and projecting from the inner surface a distance
`that is not less than approximately a distance that the
`light detector assembly extends along the inner surface,
`the light detector assembly thereby adapted to exert a
`second localized pressure against
`the body portion
`beneath the light detector assembly to stress skin
`beneath the light detector assembly.
`14. The sensor of claim 13 wherein the flexible substrate
`includes a plurality of layers.
`15. The sensor of claim 13 wherein the first and second
`localized pressures are approximately equal,
`16. An optoelectronic sensor removany securable to a
`body portion of a patient and having a light source for
`trartsilluminating the body por