(12) United States Patent
`(10) Patent No.:
`US 7,107,088 B2
`Aceti
`(45) Date of Patent:
`Sep. 12, 2006
`
`USOO7107088B2
`
`4,797,840
`4,821,982
`4,934,372
`5,036,853
`5,044,373
`5,058,586
`5,109,849
`5,115,133
`5,137,023
`5,146,091
`5,152,296
`5,167,235
`5,213,099
`5,297,554
`5,361,758
`
`1/1989
`4/1989
`6/1990
`8/1991
`9/1991
`10/1991
`5/1992
`5/1992
`8/1992
`9/1992
`10/1992
`12/1992
`5/1993
`3/1994
`11/1994
`
`Fraden
`Van Patten
`Corenrnan et a1.
`Jelfcoat et a1.
`Northeved et al.
`Heinze
`Goodman et al.
`Knudson
`Mcndclson ct al.
`Knudson
`Simons
`Seacord et al.
`Tripp, Jr.
`Glynn ct al.
`Hall et al.
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`2 210 168 A
`
`1/1989
`
`(Continued)
`
`Primary Examineriliric F. Winakur
`(74) Aztnrney, Agent, or Firmilnwenstein Sandler, PC
`
`(57)
`
`ABSTRACT
`
`PULSE OXIMETRY METHODS AND
`APPARATUS FOR USE WITHIN AN
`AUDITORY CANAL
`
`Inventor:
`
`John Gregory Aceti, West Windsor, N .1
`(US)
`
`Assignee: Sarnoff Corporation, Princeton, NJ
`(US)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 190 days.
`
`Appl. No.: 10/847,678
`
`Filed:
`
`May 17, 2004
`Prior Publication Data
`
`US 2005/0049471 A1
`
`Mar. 3, 2005
`
`Related US. Application Data
`
`Provisional application No. 60/497,890, filed on Aug.
`25, 2003.
`
`Int. Cl.
`(2006.01)
`A61B 5/00
`(2006.01)
`A611} 5/02
`US. Cl.
`..................................... .. 600/340, 600/502
`Field of Classification Search .............. .. 600/310,
`600/322, 323, 340, 344, 500, 502, 549
`See application file for complete search history.
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`2,414,747
`3,858,574
`3,910,257
`4,312,358
`4,621,643
`4,662,360
`4,754,748
`4,790,324
`
`>>>>>>>>
`
`1/1947
`1/l975
`10/1975
`1/1982
`11/1986
`5/1987
`7/1988
`12/1988
`
`Kirschhaum
`Page
`Fletcher et a1.
`Barney
`New, Jr. et al.
`O’Ilara et al.
`Antowski
`O‘Hara et al.
`
`US. Patent No. 8,929,965
`
`Methods and apparatus for detecting oxygen saturation
`levels in blood from within an auditory canal of a living
`being proximal to a tympanic membrane are disclosed. The
`auditory canal is lined with tissue and includes a proximal
`bend and a distal bend located between the proximal bend
`and the tympanic membrane. Oxygen levels are detected by
`emitting one or more wavelengths of light
`into a first
`position on the tissue of the auditory canal in a first region
`defined by the distal bend and the tympanic membrane. The
`wavelengths of light are then sensed at a second position on
`the tissue of the auditory canal in the first region. A blood
`oxygen saturation level and/or pulse rate is then calculated
`responsive to intensity infonnation corresponding to the
`wavelengths of light detected at the second position.
`
`18 Claims, 6 Drawing Sheets
`
`V/«200
`
`
`
`Apple Inc.
`APLl 01 7
`
`Apple Inc.
`APL1017
`U.S. Patent No. 8,929,965
`
`0001
`
`FITBIT, Ex. 1017
`
`

`

`US 7,107,088 B2
`Page 2
`
`>>>>>>>>>>>>
`
`5.469,855
`5.626,139
`5.673,692
`5.812,992
`5.895,371
`6.004,274
`6.047,205
`6053,8257
`6075,443
`6.078,829
`6,080,110
`6,115,621
`6.205,227
`6.231,560
`6.253,871
`6.254,526
`6.283,915
`6.289309
`
`Pompei et al.
`Szeles et 31.
`Schulze et 31,
`de Vries
`Levitas et al.
`Nolan at 211,
`Pompei
`Levitas et a1.
`Schepps el al.
`Uchida et 31.
`Thorgersen
`Chin
`Mahoney et a1.
`Bui et a1.
`Aceti
`Juneau at 211,
`Aceti et al.
`deVries
`
`FOR
`
`302 945 A
`2
`VVO 97/09927
`
`WO 1/17109 A1
`
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`6,358,216
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`6,556,852
`6,579,242
`6.691.087
`2001/0033664
`2002/0006209
`2002/0015506
`2002/0027996
`2003/0092975
`
`B1
`C11111 61 211.
`1/2002
`B1
`Kraus et al.
`3/2002
`B1
`Bui ct al.
`6/2002
`B1
`6/2002
`Sj ursen et al.
`B1
`Accti ct a1.
`10/2002
`B1
`Achulze et al.
`4/2003
`Bui et a],
`6/2003
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`Palm et :11.
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`Poux et al,
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`A1
`1/2002
`Mahoncy ct al.
`A1
`Aceti et al.
`2/2002
`Leedom et a1,
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`A1
`5/2003
`Casscells, III et al.
`
`
`7 IGN PAT
`7 N 1 DOCUMENTS
`
`U.S. PATENT DOCUMENTS
`1 1/ 199 5
`5/ 1997
`10/ 1997
`9/ 1998
`4/1999
`12/ 1999
`4/2000
`4/2000
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`6/2000
`9/2000
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`7/2001
`7/2001
`9/2001
`9/2001
`
`/2001
`
`0002
`
`FITBIT, Ex. 1017
`
`

`

`6002291D...eS
`
`Sheet 1 of 6
`
`US 7,107,088 B2
`
`U.S. Patent
`
`0003
`
`FITBIT, Ex. 1017
`
`

`

`6002291D...eS
`
`Sheet 2 of 6
`
`US 7,107,088 B2
`
`U.S. Patent
`
`0004
`
`FITBIT, Ex. 1017
`
`

`

`Sep. 12, 2006
`
`Sheet 3 of 6
`
`U.S. Patent
`
`US 7,107,088 B2
`
`0005
`
`FITBIT, Ex. 1017
`
`

`

`Sep. 12, 2006
`
`Sheet 4 of 6
`
`U.S. Patent
`
`US 7,107,088 B2
`
`0006
`
`FITBIT, Ex. 1017
`
`

`

`Sep. 12, 2006
`
`Sheet 5 of 6
`
`U.S. Patent
`
`US 7,107,088 B2
`
`0007
`
`FITBIT, Ex. 1017
`
`

`

`U.S. Patent
`
`Sep. 12, 2006
`
`Sheet 6 of 6
`
`US 7,107,088 B2
`
`of detected light.
`
`Detect light of the at least two wavelengths at a second position on
`the vascular tissue of the auditory canal in the region defined by the
`distal bend and the tympanic membrane.
`
`Emit light of at least two wavelengths into a first position on the
`vascular tissue of the auditory canal in a region defiend by the distal
`bend and the tympanic membrane.
`
`Calculate oximetry levels responsive to the at least two wavelengths
`
`0008
`
`FITBIT, Ex. 1017
`
`

`

`US 7,107,088 B2
`
`1
`PULSE OXIMETRY VIETHODS AND
`APPARATUS FOR LSE WITHIN AN
`AUDITORY CANAL
`
`0009
`
`FIG. 1 show a cross-sectional anatomical view of an
`auditory canal 100 in the transverse plane of a portion 102
`of a head. The auditory canal 100 is generally S-shaped and
`can be described as having three regions. A first region 20 is
`the medial concha cavity, which is surrounded by cartilagi-
`nous tissue 22. A second region 23, which is separated from
`the first region 20 by a first bend 30 (the “proximal bend”),
`is also surrounded by cartilaginous tissue 22. A third region
`25, which is separated from the second region 23 by a
`second bend 31 (the “distal bend”), defines the final auditory
`canal region near the tympanic membrane 26 and is sur-
`rounded by dense bony tissue 27.
`Vascular tissue 28 covering the first and second regions 20
`and 23 is relatively thick and has a well developed subcu—
`taneous layer that allows some expansion to occur. In
`contrast, vascular tissue 29 covering the third region 25 is
`relatively thin and, thus, little or no tolerance for expansion
`exists in this region.
`Mandibular motion associated with activities such as
`talking, chewing, yawning, and biting deforms the first and
`second regions 20 and 23 of the auditory canal 100. This
`deformation is generally caused by the asymmetric stresses
`from the actions of the mandibular condyle 33 on neighbor—
`ing cartilaginous tissue 22. These deformations have radial
`components, e.g. constrictions, and axial components, i.e.
`inward and outward motion, which may result in motion
`artifacts in known oximetry sensors positioned within the
`first or second regions 20 and 23. The third region 25, which
`is surrounded by bony tissue 27,
`is less susceptible to
`deformation due to mandibular motion. Additional details
`regarding the auditory canal may be found in U.S. Pat. No.
`5,701,348, which is incorporated fully herein by reference.
`FIG. 2 depicts an exemplary oximetry sensor 200 and will
`be described with reference to the auditory canal 100 of FIG.
`1. The oximetry sensor 200 is configured to measure oxygen
`saturation levels in the vascular tissue 29 within the third
`region 25 of the auditory canal 100. A first portion 202 of the
`oximetry sensor 200 is configured for placement
`in the
`second region 23 of the auditory canal 100, i.e., between the
`first bend 30 and the second bend 31. The first portion 202
`
`2
`reference numerals. This emphasizes that, according to
`common practice, the various features of the drawings are
`not drawn to scale. On the contrary, the dimensions of the
`various features are arbitrarily expanded or reduced for
`clarity. When a plurality of similar elements are present, a
`single reference numeral may be assigned to the plurality of
`similar elements with a small letter designation referring to
`specific elements. When referring to the elements collec-
`tively or to a non-specific one or more of the elements, the
`small letter designation may be dropped. Included in the
`drawings are the following figures:
`FIG. 1 is a cross sectional anatomical illustration of an
`auditory canal and surrounding structure;
`FIG. 2 is a cross-sectional View of an exemplary oximetry
`sensor in accordance with the present invention;
`FIG. 2A is a perspective view of an alternative exemplary
`oximetry sensor in accordance with the present invention;
`FIG. 3 is a surface view of a portion of an exemplary outer
`surface of the oximetry sensor of FIG. 2;
`FIGS. 4A, 4B, and 4C are cross—sectional views of
`exemplary portions of the oximetry sensor; anc
`FIG. 5 is a flow chart of exemplary steps for determining
`oximetry levels in accordance with the present invention.
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`
`
`
`
`
`
`
`CROSS REFER *NC a TO R AI ATED
`APPLICATION
`
`This application claims the benefit of US. Provisional
`Application No. 60/497,890, filed Aug. 25, 2003, the con-
`tents of which are incorporated herein by reference.
`FIELD OF THE INVENTION
`
`invention relates to the field of medical
`The present
`devices and, more particularly, to noninvasive pulse oxim-
`etry methods and apparatus for use inside an auditory canal
`of a living being.
`
`
`
`BACKGROUND OF THE INVENTION
`
`.
`
`An oximeter calculates blood oxygen saturation levels
`within a living being from the different rates at which
`oxygenated hemoglobin (oxyhemoglobin) and reduced
`hemoglobin (deoxyhemoglobin) within vascular tissue of
`the living being absorb light of different wavelengths. Typi-
`cally, two wavelengths of light are used where one wave-
`length is much less sensitive to blood oxygen saturation
`levels than the other. The wavelength of light that is less
`sensitive to oxygen saturation levels serves as a constant
`against which the wavelength of light that is more sensitive
`to oxygen saturation levels is compared in order to calculate
`blood oxygen saturation levels.
`The measurement of oxygen saturation levels (“oxim—
`etry”) is a critical physiologic measurement for critical care
`patients. Presently, sensors for use with oximeters to mea-
`sure oxygen saturation levels in vascular tissue are designed
`for placement on a finger, ear lobe, foot, or in an outer
`portion of the auditory canal. These sensors are subject to
`motion artifacts that may result in inaccurate measurements.
`Accordingly, improved oximetry methods and apparatus are
`needed that are not subject to this limitation. The present
`invention addresses this need among others.
`
`SUMNIARY OF TI IE INVENTION
`
`The present invention is embodied in methods and appa-
`ratus for detecting oxygen saturation levels in blood from
`within an auditory canal of a living being proximal to a
`tympanic membrane. The auditory canal is lined with tissue
`and includes a proximal bend and a distal bend located .
`between the proximal bend and the tympanic membrane.
`Oxygen levels are measured by emitting one or more
`wavelengths of light into a first position on the tissue of the
`auditory canal in a first region defined by the distal bend and
`the tympanic membrane; sensing the wavelengths of light at
`a second position on the tissue of the auditory canal in the
`first region, the second position being spaced from the first
`position; and calculating at least one of (i) a blood oxygen
`saturation level and (ii) a pulse rate responsive to intensity
`information corresponding to the wavelengths of light
`detected at the second position.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention is best understood from the following
`detailed description when read in connection with the
`accompanying drawings, with like elements having the same
`
`0009
`
`FITBIT, Ex. 1017
`
`

`

`0010
`
`3
`includes a distal end 204 that extends toward the tympanic
`membrane 26 when the oximetry sensor 200 is positioned
`within the auditory canal 100. In an exemplary embodiment,
`the first portion 202 includes an outer surface (shell) 206 that
`is relatively rigid and shaped to conform to the contours of 5
`the second region 23.
`In an exemplary embodiment, the outer surface 206 of the
`first portion 202 is substantially smooth and the first portion
`202 further includes a hollow body portion 208 that extends
`from the distal end 204 to an outer end 210 that is substan—
`tially opposite the distal end 204. The hollow body portion
`208 defines an elongated passage 209 that extends between
`the outer end 210 and the distal end 204 of the first portion
`202 for communication of acoustic signals through the first
`portion 202. The hollow body portion 208 may be config—
`ured such that light is not passed by the hollow passage to
`the vascular tissue 29 in the third region 25.
`In an alternative exemplary embodiment, the outer sur-
`face 206 of the first portion 202 includes one or more
`protrusions (fins, bumps, etc.) that form channels extending
`from the outer end 210 to the distal end 204 of the first
`portion 202 in addition to, or instead of, the hollow body
`portion 208. FIG. 3 represents an exemplary portion 300 of
`the outer surface 206 (FIG. 2) between the outer end 210 and
`the distal end 204. The exemplary portion 300 includes
`protrusions (represented by a first protrusion 302, a second
`protrusion 304, and a third protrusion 306). The illustrated
`first and second protrusions 302 and 304 define a first
`channel 308 and the second and third protrusions 304 and
`306 define a second channel 310. The channels 308 and 310
`each have a “maze-like” configuration that doubles back on
`itself between the outer end 210 and the distal end 204 to
`allow acoustic signals to pass through the second region 23
`(FIG. 1) to a second portion 212 031G. 2) while blocking
`light from reaching the vascular tissue 29 in the third region
`25.
`In an exemplary embodiment, the protrusions are sized to
`comfortably support the first portion 202 within the auditory
`canal 100 while allowing air (sound) to [low freely past the
`first portion 202. The protrusions act to centrally hold the
`first portion 202 in the second region 23 ofthe auditory canal
`100 and comfortably touch the vascular tissue 28 of the
`auditory canal 100. Each protrusion may have a flat surface
`where it contacts the vascular tissue 28 to minimize dis-
`comfort, Although three protrusions are illustrated, fewer or
`more protrusions may be formed on the outer surface 206.
`Positioning a device within the auditory canal 100 nega—
`tively aJTect hearing, however, a hole larger than 2 mm, or
`an e ‘ective passage(s) having an area equivalent to a 2 mm
`hole or larger will substantially pass most low to high audio ,
`frequencies.
`Referring back to FIG. 2, a second portion 212 of the
`oximetry sensor 200 is configured for placement in the third
`region 25 of the auditory canal 100, i.e., between the second
`bend 31 and the tympanic membrane 26. The second portion
`212 includes optically transparent portions 224 and optically
`blocking portions 226 for use in measuring oximetry levels
`within the vascular tissue 29 of the third region 25, which is
`described in further detail below. The optically transparent
`portions 224 form channels and/or islands within the opti—
`cally blocking portions 226. An outer surface 214 of the
`second portion 212 is configured to abut at least a portion of
`the vascular tissue 29 lining the auditory canal 100 in the
`third region 25. Due to the dense bony tissue 27 surrounding
`the third region 25, positioning the second portion 212
`within the third region 25 effectively isolates the second
`portion 212 from being directly affected by mandibular
`
`Referring back to FIG. 2. an emitter 228 is positioned
`within the oximetry sensor 200 to emit light of two or more
`wavelengths from a first optically transparent portion 224a
`ofthe second portion 212 into a corresponding first position
`of the vascular tissue 29 when the oximetry sensor 200 is
`positioned within the auditory canal 100. The illustrated
`emitter 228 includes a first light source 230, a first light
`channel 232, a second light source 234, and a second light
`channel 236. In an exemplary embodiment, the first and
`second light sources 230 and 234 are positioned within the
`first portion 202 and the first and second light channels 232
`and 234 are configured to direct light from the first and
`
`
`
`
`US 7,107,088 B2
`
`,
`
`4
`motion, thereby reducing oximetry false alarms associated
`with motion artifacts. Additionally. positioning the second
`portion 212 past the second bend 31 tends to “lock” the
`oximetry sensor 200 in position.
`In an exemplary embodiment. the second portion 212 is
`movably coupled to the first portion 202. The second portion
`212 includes a proximal end 216 and a tympanic end 218
`that extends toward the tympanic membrane 26 when the
`oximetry sensor 200 is positioned within the auditory canal
`100. Although positioning the second portion 212 within the
`third region 25 effectively isolates the second portion from
`being directly affected by mandibular motion, the second
`portion 212 may be indirectly affected by mandibular
`motion transferred to the second portion 212 through the
`first portion 202. Movably coupling the second portion 212
`to the first portion 202 reduces the effect of this indirect
`mandibular motion on the second portion 212,
`thereby
`further reducing oximetry measurement false alarms due to
`motion artifacts.
`In an exemplary embodiment, the second portion 212
`further includes a hollow body portion 220 that defines an
`elongated passage 222 extending between the proximal end
`216 and the tympanic end 218 of the second portion 212.
`The hollow body portion 220 is configured to communicate
`acoustic signals through the second portion 212 between the
`first portion 202 and the tympanic membrane 26. If each of
`the first and second portions 202 and 212 include elongated
`passages (e.g.. elongated passages 209 and 222). acoustic
`signals originating from outside the auditory canal 100 may
`pass to the tympanic membrane 26.
`In an exemplary embodiment, the second portion 212 is
`made of a flexible elastomer, which renders the second
`portion 212 movable with respect to the first portion 202.
`The flexible elastomer facilitates the navigation of the
`typical, nominally S-shaped centerline path of the auditory
`canal 100. The second portion 212 may be constructed of a
`low modulus, low durometer material to provide a high level
`of comfort for the user even when it is inserted into the third
`region 25 of the auditory canal 100. In addition, the hollow
`body portion 220 may be substantially tubular in shape and
`elongated to permit a continuum of deformations along its
`length so that its axis can conform to the axis of the auditory
`canal in the third region 25.
`In an alternative exemplary embodiment, as depicted in
`, FIG. 2A, a mechanical joint 270 may be positioned between
`the first portion 202 and the second portion 212 to render the
`second portion 212 movable relative to the first portion 202.
`The illustrated mechanical joint 270 includes a ball portion
`272 and a ball receiving portion 274 configured to movably
`engage the ball portion 272. Examples of suitable mechani-
`cal joints may be fotmd in US. Pat. No. 6,205,227 to
`
`Mahoney et
`al.
`titled PERITYMPANIC HEARING
`
`INSTRUMENT, which is commonly assigned with the
`present application and incorporated fully herein by refer-
`ence.
`
`0010
`
`FITBIT, Ex. 1017
`
`

`

`US 7,107,088 B2
`
`0011
`
`6
`receiving portion may radially overlap, but be separated in
`a longitudinal direction by the optically blocking portion
`226, e.g., along the length of the elongated passage 222
`(FIG. 2) extending through the second portion 212.
`Referring back to FIG. 2, the oximetry circuitry 244 is
`configured to process information corresponding to the two
`or more wavelengths of light received by the detector 238.
`In addition, the oximetry circuitry 244 may be configured to
`control the emitter 228. The oximetry circuitry 244 may be
`coupled to the emitter 228 and the detector 238 via traces of
`a circuit board 246. The oximetry circuitry 224 may be
`configured to calculate an oximetry value based on the
`received two or more wavelengths of light. In addition, the
`oximitry circuitry 244 may be configured to calculate pulse
`rate. Suitable methods for calculating oximetry levels and
`pulse rates will be understood by those of skill in the art.
`The exemplary oximetry circuitry 244 further includes an
`emitter 248 for wireless transmission of information related
`to the two or more wavelengths of light and/or a port 250 for
`‘ wired transmission of information related to the two or more
`wavelength of light. The information related to the two or
`more wavelengths of light may be values calculated by the
`oximetry circuitry 244 or raw data detected by the detector
`238. A suitable oximetry circuit for use in the present
`invention will be understood by those of skill in the art.
`FIG. 5 depicts a flow chart 500 of exemplary steps for
`detecting oxygen saturation levels in blood from within an
`auditory canal of a living being. The steps are described with
`reference to FIGS. 1 and 2.
`At block 502, the emitter 228 emits light of two or more
`wavelengths into a first position on the vascular tissue 29 of
`the auditory canal 100 in the third region 25, which is
`defined by the distal bend 31 and the tympanic membrane
`26. At least one of the wavelengths of light is much less
`sensitive to blood oxygen saturation levels than at least one
`of the other wavelengths of light. The wavelength of light
`that is sensitive to blood oxygen saturation levels may be the
`isobestic wavelength, which for oxygenated blood is 805
`nm, e.g., infrared light. After the oximetry sensor 200 is
`positioned within the auditory canal 100, the emitter 204
`emits the two or more wavelengths of light, e.g., from light
`sources 230 and 234, responsive to the oximetry circuitry
`244.
`In an exemplary embodiment, the oximetry circuitry 244
`is configured to modulate the emitter 228 to cause a first
`light source, e.g., light source 230, to emit light for one-third
`(1/3) of a proposed cycle time; to cause a second light source,
`e.g., light source 234, to emit light during a second one-third
`of the cycle time; and to cause no light to be emitted during
`a final one-third ofthe cycle time. During the period of time
`in which no light is emitted, the detector 238 may measure
`background light intensity levels for subtraction from the
`measure light intensity signals when light is being emitted to
`increase accuracy.
`In an exemplary embodiment, the wavelengths of light are
`generated in the first portion 202 and are passed to the
`emitting optically transparent portion 224a of the second
`portion 212, e.g., via optical fibers 232 and 234, where they
`are emitted into the first position on the vascular tissue 29.
`In an alternative exemplary embodiment, the wavelengths of
`light originate in the second portion 212 responsive to
`electrical signal from the oximetry circuitry 244.
`At block 504, the detector 238 detects the intensity of the
`two or more frequencies of light at a second position on the
`vascular tissue 29 of the auditory canal 100 in the third
`region 25. The second position is spaced from the first
`position and the light detected by the detector 228 is light
`
`
`
`5
`to the first optically
`second light sources, respectively,
`transparent portion 224a. In an alternative embodiment, the
`light sources 230 and 234 may be positioned within the
`second portion 212 with leads (not shown) for powering the
`light sources extending from a power source (not shown) in
`the first portion 202 to the first and second light sources in
`the second portion 212. The first and second light sources
`230 and 234 may be light emitting diodes (LEDs, e.g., a 660
`nm IFD and an 805 nm IFD) and the first and second light
`chamiels 232 and 236 may be optical fibers.
`A detector 238 is positioned within the oximetry sensor
`200 to detect light of the two or more wavelengths out of a
`second position of the vascular tissue 29 impinging a
`corresponding second optically transparent portion 22417 of
`the second portion 212 when the oximetry sensor 200 is
`positioned within the auditory canal 100. The illustrated
`detector 238 includes a photodetector 240 (e.g., a photo
`diode) and a third light channel 242 (e.g., an optical fiber).
`In an exemplary embodiment,
`the photodetector 240 is
`positioned within the first portion 202 and the third light
`channel 242 is configured to direct
`light
`impinging the
`second optically transparent portion 224/3 of the second
`portion 212 through the second portion 212 to the photodc-
`tector 240 in the first portion 202. In an alternative exem—
`plary embodiment, the photodetector 240 may be positioned ,
`within the second portion 212 with a lead (not shown)
`extending from the photodetector 240 to oximetry circuitry
`244 in the first portion 202. The first and second optically
`transparent portions 224a anc 2241) may form channels on
`the surface of the second portion 212 for respectively
`emitting and detecting light along the channels to maximize
`coupling and to limit the e'"ects of blockage do to wax
`build—up.
`FIGS. 4A, 4B. and 4C deoict cross sectional views of
`exemplary second portions 212 for delivering light to the
`first and second positions of the vascular tissue in the third
`region 25. The cross sectional views each include an opti-
`cally blocking portion 226 and optically transparent portions
`224. The illustrated cross sectional second portions each
`include two transparent portions 2247a light emitting opti-
`cally transparent portion 224a and a light receiving optically
`transparent portion 22417. The light emitting portion 224a is
`coupled to the first and second light sources 230 and 234
`(FIG. 2) and the light receiving portion 2241) is coupled to
`the photodetector 240, e.g., via optical fibers 232, 236, and
`242. The light emitting portion 224a emits light from the
`light sources to the first position of the vascular tissue 29
`when the oximetry sensor 200 is positioned within the
`auditory canal and the light receiving portion 224]) collects
`light from the second position ofthe vascular tissue 29 when ,
`the oximetry sensor 200 is positioned within the auditory
`canal.
`In FIG. 4A, the light emitting portion 224a and the light
`receiving portion 22417 are radially positioned substantially
`opposite one another, e.g., about 180 degrees apart, such that
`the first and second positions on the vascular tissue are on
`opposite sides of the second portion 212 (FIG. 2). In FIG.
`4B, the light emitting portion 224a and the light receiving
`portion 224]) are radially positioned approximately 90
`degrees with respect to one another. In FIG. 4C, the light
`emitting portion 224a and the light receiving portion 22417
`are radially positioned approximately 45 degrees with
`respect to one another. In an exemplary embodiment, the
`light emitting portion 224a and the light receiving portion
`22417 are radially positioned relative to one another between
`about 5 degrees and 180 degrees. In an alternative exem-
`plary embodiment, the light emitting portion and the light
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`FITBIT, Ex. 1017
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`US 7,107,088 B2
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`that has passed through the vascular tissue 29 from the first
`position to the second position. In an exemplary embodi-
`ment,
`the detector 238 sequentially detects the light as
`emitted by the emitter 228.
`light from the second
`In an exemplary embodiment,
`position of the vascular tissue 29 impinges upon the opti—
`cally transparent portion 22417 of the second portion 212 and
`is passed to the photo detector 240 in the first portion 202,
`e.g., via an optical fiber 242, for detection and communica-
`tion to the oximetry circuitry 244. In an alternative exem—
`plary embodiment, the light is detected in the second portion
`and an electrical signal including intensity information cor-
`responding to the detected light is passed to the first portion,
`e.g., via a transmission line.
`As used herein, the phrase “intensity information corre—
`sponding to the two or more frequencies of light” detected
`in the third region 25 may be used to refer to the actual light
`or to an electrical signal representing the actual light. In an
`exemplary embodiment, this information passes from the
`third region 25 to another region (e.g., within the auditory
`canal or outside of the auditory canal) distinct from the third
`region 25 through a flexible coupling (e.g., a flexible second
`portion 202 coupled to the first portion 212 or a mechanical
`joint connecting the first and second portions 202 and 212).
`At block 506,
`the oximetry circuitry 244 calculates a ,
`blood oxygen saturation level responsive to the intensity
`information corresponding to the two or more wavelengths
`of light detected at the second position. Since one of the
`frequencies of light is less sensitive to oxygen saturation
`levels than the other,
`this frequency of light provides a
`“base-line” against which a frequency of light that is more
`sensitive to oxygen saturation can be compared in order to
`calculate blood oxygen saturation levels in a manner that
`will be understood by those of skill in the art. The oximetry
`circuitry 244 may alternatively or additionally calculate
`pulse rate responsive to the information in a mamier that will
`also be understood by those of skill in the art. The absolute
`strength of the signal is dynamic and cyclic being responsive
`to the pulsitile arterial blood flowipeak to peak measure-
`ments determine pulse. For a modulated light source, the
`light source should be modulated at a frequency of at least
`twice that of the highest frequency to be measured, e.g., at
`300 Hz or more to measure a pulse rate of 150 beats per
`minute or less. In accordance with this embodiment, light of
`only one wavelength is needed and, thus, only one light 45
`source (e.g., a single LED) that is sensitive to blood oxygen
`saturation levels is needed. In an exemplary embodiment,
`the oximetry circuitry 244 calculates the blood oxygen
`saturation level and/or pulse rate in a region other than the
`third region 25, e.g., within another region of the auditory ,
`canal 100 or external to the auditory canal.
`Although the invention is illustrated and described herein
`with reference to specific embodiments, the invention is not
`intended to be limited to the details shown. Rather, various
`modifications may be made in the details within the scope
`and range of equivalents of the claims and without departing
`from the invention.
`“What is claimed is:
`1. An apparatus for detecting oxygen saturation levels in
`blood from within an auditory canal of a living being
`proximal to a tympanic membrane, the auditory canal being
`lined with tissue and including a proximal bend and a distal
`bend located between the proximal bend and the tympanic
`membrane, the apparatus comprising:
`a first portion configured for placement in the auditory
`canal between the proximal bend and the distal bend,
`the first portion having a distal end extending toward
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`the tympanic membrane when the apparatus is posi—
`tioned within the auditory canal;
`a second portion movably coupled to the distal end of the
`first portion, the second portion comprising an outer
`surface configured to abut at least a portion ofthe tissue
`of the auditory canal between the distal bend and the
`tympanic membrane when the apparatus is positioned
`within the auditory canal,
`an emitter that emits light of one or more wavelengths
`from a first position on the outer surface of the second
`portion into the tissue of the auditory canal between the
`distal bend and the tympanic membrane, and
`a detector that detects the light of one or more wave-
`lengths from the tissue of the auditory canal between
`the distal bend and the tympanic membrane impinging
`upon a second position on the outer surface of the
`second portion.
`2. The apparatus of claim 1, wherein the first portion is
`substantially rigid and the second portion extends from the
`first portion and is relatively flexible such that the second
`portion is movable relative to the first portion to at least
`partially isolate the second portion from movement of the
`first portion.
`3. The apparatus of claim 1, further comprising a joint
`coupled between the distal end of the first portion and the
`second portion.
`4. The apparatus of claim 1, the second portion having a
`proximal end coupled to the distal end of the first portion and
`a tympanic end extending toward the tympanic membrane
`when the apparatus is positioned within the auditory canal,
`the second portion further comprising a first hollow body
`portion defining an elongated passage extending between the
`proximal end and the tympanic end of the second portion for
`communication of acoustic signals through the second por-
`tion between the first portion and the tympanic membrane.
`5. The apparatus of claim 4, wherein the first portion has
`an outer end portion substantially opposite the distal end, the
`first portion further comprising a second hollow body por—
`tion defining an elongated passage extending between the
`outer end and distal end of the first