Case: 22-1631 Document: 48 Page: 1 Filed: 09/12/2023
`
`NOTE: This disposition is nonprecedential.
`
`United States Court of Appeals
`for the Federal Circuit
`______________________
`
`MASIMO CORPORATION,
`Appellant
`
`v.
`
`APPLE INC.,
`Appellee
`______________________
`
`2022-1631, 2022-1632, 2022-1633, 2022-1634, 2022-1635,
`2022-1636, 2022-1637, 2022-1638
`______________________
`
`Appeals from the United States Patent and Trademark
`Office, Patent Trial and Appeal Board in Nos. IPR2020-
`01520, IPR2020-01521, IPR2020-01536, IPR2020-01537,
`IPR2020-01538,
`IPR2020-01539,
`IPR2020-01714,
`IPR2020-01715.
`
`______________________
`
`Decided: September 12, 2023
`______________________
`
`STEPHEN W. LARSON, Knobbe, Martens, Olson & Bear,
`LLP, Irvine, CA, argued for appellant. Also represented by
`STEPHEN C. JENSEN, JAROM D. KESLER, JOSEPH R. RE;
`JEREMIAH HELM, Washington, DC.
`
` LAUREN ANN DEGNAN, Fish & Richardson P.C., Wash-
`ington, DC, argued for appellee. Also represented by
`
`

`

`Case: 22-1631 Document: 48 Page: 2 Filed: 09/12/2023
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`2
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`MASIMO CORPORATION v. APPLE INC.
`
`CHRISTOPHER DRYER, JARED HARTZMAN, WALTER KARL
`RENNER; ASHLEY BOLT, Atlanta, GA.
` ______________________
`
`Before LOURIE, PROST, and CUNNINGHAM, Circuit Judges.
`LOURIE, Circuit Judge.
` Masimo Corp. (“Masimo”) appeals from eight final
`written decisions of the United States Patent and Trade-
`mark Office (“USPTO”) Patent Trial and Appeal Board
`(“the Board”) holding nearly all claims of U.S. Patents
`10,258,265 (“the ’265 patent”), 10,292,628 (“the ’628 pa-
`tent”), 10,577,553 (“the ’553 patent”), 10,588,554 (“the ’554
`patent”), and 10,631,765 (“the ’765 patent”) (collectively,
`“the challenged patents”) unpatentable as obvious. Apple
`Inc. v. Masimo Corp., IPR2020-01520, 2022 WL 557896
`(P.T.A.B. Feb. 23, 2022) (“’1520 Decision”), J.A. 1–106; Ap-
`ple Inc. v. Masimo Corp., IRPR2020-01521, 2022 WL
`1093210 (P.T.A.B. Apr. 11, 2022) (“’1521 Decision”), J.A.
`107–98; Apple Inc. v. Masimo Corp., IPR2020-01536, 2022
`WL 562452 (P.T.A.B. Feb. 23, 2022) (“’1536 Decision”), J.A.
`199–276; Apple Inc. v. Masimo Corp., IPR2020-01537, 2022
`WL 557730 (P.T.A.B. Feb. 23, 2022) (“’1537 Decision”), J.A.
`277–358; Apple Inc. v. Masimo Corp., IPR2020-01538, 2022
`WL 557732 (P.T.A.B. Feb. 23, 2022) (“’1538 Decision”), J.A.
`359–428; Apple Inc. v. Masimo Corp., IRPR2020-01539,
`2022 WL 562219 (P.T.A.B. Feb. 23, 2022) (“’1539 Deci-
`sion”), J.A. 429–514; Apple Inc. v. Masimo Corp., IPR2020-
`01714, 2022 WL 1094551 (P.T.A.B. Apr. 6, 2022) (“’1714
`Decision”), J.A. 515–91; Apple Inc. v. Masimo Corp.,
`IPR2020-01715, 2022 WL 1093219 (P.T.A.B. Apr. 6, 2022)
`(“’1715 Decision”), J.A. 592–675. For the reasons articu-
`lated below, we reverse-in-part and affirm-in-part.
`BACKGROUND
`The challenged patents, all assigned to Masimo, are di-
`
`rected to an optical sensor for noninvasively measuring
`blood constituents, including a protruding, convex cover
`
`

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`Case: 22-1631 Document: 48 Page: 3 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`3
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`positioned over multiple light detectors and emitters. Rep-
`resentative claim 1 of the ’628 patent is reproduced below.
`1. A noninvasive optical physiological sensor com-
`prising:
`a plurality of emitters configured to emit light into
`tissue of a user;
`a plurality of detectors configured to detect light that
`has been attenuated by tissue of the user, wherein
`the plurality of detectors comprise at least four de-
`tectors;
`a housing configured to house at least the plurality
`of detectors; and
`a light permeable cover configured to be located be-
`tween tissue of the user and the plurality of detec-
`tors when the noninvasive optical physiological
`sensor is worn by the user, wherein the cover com-
`prises an outwardly protruding convex surface con-
`figured to cause tissue of the user to conform to at
`least a portion of the outwardly protruding convex
`surface when the noninvasive optical physiological
`sensor is worn by the user and during operation of
`the noninvasive optical physiological sensor, and
`wherein the plurality of detectors are configured to
`receive light passed through the outwardly protrud-
`ing convex surface after attenuation by tissue of the
`user.
`’628 patent, col. 44 ll. 36–56.
`
`Apple Inc. (“Apple”) petitioned for review of the five
`challenged patents, asserting three primary references,
`
`

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`Case: 22-1631 Document: 48 Page: 4 Filed: 09/12/2023
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`4
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`MASIMO CORPORATION v. APPLE INC.
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`Aizawa,1 Mendelson-1988,2 and/or Mendelson-799,3 in
`combination with at least one of three secondary refer-
`ences, Inokawa,4 Ohsaki,5 and/or Mendelson-2006.6 Ai-
`zawa discloses a wrist, palm-side sensor for detecting a
`pulse with a single, central emitter and a “plate-like mem-
`ber” to “improve adhesion” (e.g., contact between the sensor
`and a user’s skin). Aizawa, Figs. 1(a), 1(b), 2, ¶ 13. Men-
`delson-1988 discloses a flat, forehead oxygen sensor with
`multiple detectors around a central emitter. Mendelson-
`1988, Fig. 2. Mendelson-799 discloses a similar arrange-
`ment but with three centrally clustered emitters. Mendel-
`son-799, Fig. 7.
` Mendelson-2006
`focuses on the
`transmission of data from an optical sensor. Mendelson-
`2006, Abstract. Inokawa discloses a wrist sensor with a
`convex cover, emitters on the periphery, and a single detec-
`tor in the center. Inokawa, ¶¶ 58–59, Fig. 2. Ohsaki
`
`1 U.S. Patent Application Publication 2002/0188210
`A1 (filed May 23, 2002, published Dec. 12, 2002), J.A.
`3242–48 (“Aizawa”).
`2 Yitzhak Mendelson et al., Design and Evaluation
`of a New Reflectance Pulse Oximeter Sensor, 22 ASS’N FOR
`THE ADVANCEMENT OF MED. INSTRUMENTATION 167 (1988),
`J.A. 3358–64 (“Mendelson-1988”).
`3 U.S. Patent 6,801,799 B2 (filed Feb. 6, 2003, issued
`Oct. 5, 2004), J.A. 155578–93 (“Mendelson-799”).
`4 Japanese Patent Application Published 2006-
`296564 A (filed Apr. 18, 2005, published Nov. 2, 2006), J.A.
`3249–95 (“Inokawa”).
`5 U.S. Patent Application Publication 2001/0056243
`A1 (filed May 11, 2001, published Dec. 27, 2001), J.A.
`3352–57 (“Ohsaki”).
`6 YITZHAK MENDELSON ET AL., A WEARABLE
`REFLECTANCE
`PULSE
`OXIMETER
`REMOTE
`FOR
`PHYSIOLOGICAL MONITORING (Proceedings of the 28th
`IEEE EMBS Annual International Conference, Aug. 30–
`Sep. 3, 2006), J.A. 23200–03 (“Mendelson-2006”).
`
`

`

`Case: 22-1631 Document: 48 Page: 5 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`5
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`discloses a sensor with a convex cover worn on the “back
`side” (i.e.., watch side) of a user’s wrist and that reduces
`slippage. Ohsaki, Abstract; see also id. at Fig. 1, ¶ 23.
`
`In the eight inter partes review (“IPR”) proceedings,
`Apple asserted a variety of motivations to combine the as-
`serted references, including: (1) improved light collection,
`(2) improved adhesion, (3) improved detection efficiency,
`and (4) improved protection of the sensor elements. The
`improved light collection theory was based, in part, on
`what the Board and parties referred to as the “greatest cur-
`vature theory,” meaning that light concentration would in-
`crease where the curvature of a lens’s surface is the
`greatest—in Apple’s proposed combinations, allegedly at
`the peripheral detectors, not directly at the center.
` Masimo challenged each of the proffered motivations to
`combine, including arguing that (1) a convex lens would
`condense light toward the center, away from the peripheral
`detectors in Apple’s combinations; (2) Apple’s arguments
`contradicted admissions made by its expert witness; and
`(3) Ohsaki only teaches improved adhesion with a watch-
`side sensor, and the same benefits would not be achieved
`with Aizawa’s palm-side sensor, which achieves adhesion
`through its flat plate. Masimo further argued that the
`greatest curvature theory was belatedly raised in Apple’s
`Reply Brief. In addition, Masimo challenged Apple’s as-
`serted reasonable expectations of success and the refer-
`ences’ alleged disclosure of every claim element, including
`the specific protrusion heights required by claims 11, 17,
`and 28 of the ’554 patent and claims 12, 18, and 29 of the
`’765 patent.
`The Board ultimately found that each challenged claim
`would have been obvious over the combination of refer-
`ences, except for independent claim 13 of the ’554 patent.
`
`

`

`Case: 22-1631 Document: 48 Page: 6 Filed: 09/12/2023
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`6
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`MASIMO CORPORATION v. APPLE INC.
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`Across the eight IPRs, the Board found the following moti-
`vations to combine7:
`Combinations Appealed
`(Relevant Claims)
`Aizawa-Inokawa
`’1520 IPR: all challenged claims
`’1521 IPR: all challenged claims
`Aizawa-Inokawa-Ohsaki
`’1520 IPR: all challenged claims
`’1521 IPR: all challenged claims
`Aizawa-Inokawa-Ohsaki
`’1537 IPR: claims 1–6, 9–18,
`20–24, 29
`
`Board’s Found Motiva-
`tion(s) to Combine
`Improve light collection
`
`Improve adhesion
`Improve detection efficiency
`
`Improve adhesion
`Improve detection efficiency
`Protect sensor elements
`Improve adhesion
`Improve detection efficiency
`Protect sensor elements
`
`Aizawa-Inokawa-Ohsaki-
`Mendelson-2006
`’1537 IPR: claims 7, 10
`’1539 IPR: all challenged claims
`’1715 IPR: all challenged claims
`Mendelson-1988-Inokawa
`’1520 IPR: claims 1, 2, 4, 14,
`17–25, 26–30
`’1521 IPR: all challenged claims
`Mendelson-799-Ohsaki
`’1536 IPR: all challenged claims
`’1538 IPR: all challenged claims
`
`Improve light collection
`
`Improve adhesion
`Improve detection efficiency
`Protect sensor elements
`
`
`7 This chart is based on a chart included in Appellee
`Br. at 21. Masimo did not dispute that the chart was an
`accurate summary of the Board’s motivation to combine
`findings.
`
`

`

`Case: 22-1631 Document: 48 Page: 7 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`7
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`Board’s Found Motiva-
`tion(s) to Combine
`
`Combinations Appealed
`(Relevant Claims)
`’1714 IPR: all challenged claims
`Masimo appealed to this court. We have jurisdiction
`under 28 U.S.C. § 1295(a)(4)(A).
`DISCUSSION
` Masimo raises a number of arguments on appeal,
`which fall into five main categories: (1) that the Board
`erred in relying on theories not raised by either party, (2)
`that the Board erred in failing to consider contrary evi-
`dence and admissions, (3) that the Board erred in relying
`on the allegedly belatedly raised “greatest curvature the-
`ory,” (4) that the Board’s factual findings underlying its ob-
`viousness determination were unsupported by substantial
`evidence, and (5) that the Board erred in finding that de-
`pendent claims 14–18 of the ’554 patent would have been
`obvious when it found independent claim 13 nonobvious.
`We address each argument in turn.
`I
` Masimo argues that, in rendering its decisions, the
`Board relied on its own theories not asserted by either
`party, thereby depriving it of the opportunity to respond.
`In the ’1520 and ’1521 IPRs, in response to Masimo’s
`argument that Aizawa’s plate’s flatness provided its adhe-
`sion benefits, the Board found that Aizawa’s “improved ad-
`hesion is provided by the acrylic material . . . not the flat
`surface.” ’1520 Decision at *28; ’1521 Decision at *27.
`Masimo alleges that Apple never argued that. Appellant
`Br. at 50–51. Rather, it argues, Apple’s expert testified
`that Aizawa’s plate “doesn’t explicitly require the use of
`acrylic” and that one “can obtain the benefits associated
`with Aizawa” by using materials including but not limited
`to acrylic. J.A. 5427, 133:5–9; J.A. 5428, 134:12–14.
`
`

`

`Case: 22-1631 Document: 48 Page: 8 Filed: 09/12/2023
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`8
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`MASIMO CORPORATION v. APPLE INC.
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`In the ’1537, ’1539, and ’1715 IPRs, in response to
`Masimo’s argument that Ohsaki’s longitudinal protrusion
`successfully achieves improved adhesion by interacting
`with a user’s wrist bones, the Board found that a circular
`sensor like that in Aizawa “would also avoid the bones in
`the forearm if [the sensor] were slightly smaller.” ’1537
`Decision at *21; ’1539 Decision at *22; ’1715 Decision at
`*22. Masimo alleges that Apple never argued that, and
`that there is no evidence that a person of ordinary skill in
`the art would have reduced Aizawa’s sensor size, particu-
`larly when it was already “small.” Appellant’s Br. at 65–66
`(citing Mendelson-2006).
`Under the Administrative Procedure Act’s notice pro-
`visions, as relevant to Board proceedings, patent owners
`“shall be timely informed of . . . the matters of fact and law
`asserted” in IPRs, 5 U.S.C. § 554(b)(3), and the Board
`“shall give all interested parties opportunity for . . . the
`submission and consideration of facts [and] arguments,” id.
`§ 554(c)(1). The Board, therefore, “must base its decision
`on arguments that were advanced by a party, and to which
`the opposing party was given a chance to respond.” In re
`Magnum Oil Tools Int’l, Ltd., 829 F.3d 1364, 1381 (Fed.
`Cir. 2016); see also Apple Inc. v. Corephotonics, Ltd., No.
`2022-1350, slip op. at 13 (Fed. Cir. Sep. 11, 2023) (finding
`the Board erred when its analysis focused on “an issue that
`no party meaningfully raised or asserted was relevant”);
`Alacritech, Inc. v. Intel Corp., 966 F.3d 1367, 1372 (Fed.
`Cir. 2020) (finding that the Board erred where its “reason-
`ing appear[ed] to be untethered to either party’s position”).
`The Board may in certain circumstances rely on its own
`readings of references. Belden Inc. v. Berk-Tek LLC, 805
`F.3d 1064, 1074 (Fed. Cir. 2005). These readings, however,
`must still “be supported by substantial evidence, and its
`decisions must be reached only after the parties have been
`provided fair notice and an opportunity to be heard.” Ap-
`ple, No. 2022-1350 at 14–15.
`
`

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`MASIMO CORPORATION v. APPLE INC.
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`9
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`The Board’s conclusions on those two points were not
`
`supported by the petitions nor merely “simple point[s]” that
`the Board could have easily deduced from the face of the
`reference. Belden, 805 F.3d at 1074. Indeed, Apple does
`not argue that it presented those theories at any point in
`the IPRs. See Appellee Br. at 34–36. However, even if the
`Board may have erred in relying on its own theories, that
`is of no consequence here because they are not essential to
`its determinations.
`
`The Board relied on those allegedly new arguments in
`rejecting Masimo’s arguments against adhesion as a moti-
`vation to combine. But adhesion is not the only motivation
`to combine that the Board relied on. The Board also found
`that improved light collection, improved detection effi-
`ciency and, in all but the ’1520 and ’1521 IPRs, improved
`protection of the sensor elements provided motivations to
`combine the asserted references. See infra, Section IV.A;
`Oral Arg. at 11:42–51 (“And you see that whenever the
`Board relied on the motivation to increase adhesion, with
`Ohsaki, then the Board would also rely on a motivation to
`provide protection.”). Therefore, even if the Board erred by
`relying on these theories as part of its finding of adhesion
`as a motivation to combine, it was, at most, harmless error.
`II
` Masimo argues that the Board failed to consider evi-
`dence and admissions by Apple and its expert witness that
`were contrary to the Board’s findings. Masimo cites sev-
`eral nonprecedential opinions in support of its argument.
`See Appellant Br. at 32–33 (first citing Cook Grp. Inc. v.
`Boston Sci. Scimed, Inc., 809 F. App’x 990, 999 (Fed. Cir.
`2020) (“The Board erred in refusing to consider [peti-
`tioner’s] admission[s] when it was weighing the evi-
`dence . . . .”); and then citing PPC Broadband, Inc. v. Iancu,
`739 F. App’x 615, 623 (Fed. Cir. 2018) (vacating obvious-
`ness decision where Board failed to address expert’s admis-
`sions)). Masimo is correct that the Board has an obligation
`
`

`

`Case: 22-1631 Document: 48 Page: 10 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`to look at evidence properly before it, even if it detracts
`from its determination. See Parus Holdings, Inc. v. Google
`LLC, 70 F.4th 1365, 1372 (Fed. Cir. 2023) (discussing Aqua
`Prods. v. Matal, 872 F.3d 1290, 1325 (Fed. Cir. 2017) (en
`banc)). However, the Board did consider the evidence and
`argument that Masimo claims were overlooked. The Board
`simply rejected those arguments or found the contrary ev-
`idence outweighed by other supporting evidence.
` Masimo asserts that at least the following allegations
`were not properly considered: (1) Apple’s and its expert’s
`alleged admission that a convex cover would concentrate
`light toward the sensor’s center, rather than toward the pe-
`ripheral detectors, (2) Aizawa’s alleged teaching of its flat
`plate providing benefits, e.g., adhesion, (3) Inokawa’s al-
`leged failure to teach benefits of a convex lens, (4) the pro-
`posed combination’s elimination of Ohsaki’s convex cover
`aligning with a user’s wrist bones, and (5) the proposed
`combination’s potential creation of air gaps between the
`sensor and a user’s skin. But the Board considered each of
`those allegations. For example, as discussed above, the
`Board considered and rejected Masimo’s argument that Ai-
`zawa’s adhesion benefits were attributable to its sensor
`cover being flat and the alignment of Ohsaki’s protrusion
`with wrist bones. See, supra, Section I. The Board also
`thoroughly considered whether light would be condensed
`at the center, or elsewhere, citing testimony of Apple’s ex-
`pert stating that the light-focusing properties of a convex
`lens do not demonstrate “that a convex lens directs all light
`to the center.” See, e.g., ’1521 Decision at *20, 22–24. The
`Board also found that Apple did “not propose including any
`air gaps” in its combination. See, e.g., ’1536 Decision at *18.
`And the Board found that “Inokawa demonstrates that it
`was known in the art prior to the ’265 patent to use a lens
`to focus diffuse light reflected from body tissue on to the
`light detecting elements of a wrist-worn pulse sensor, to in-
`crease the light gathered by the sensor and thereby
`
`

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`Case: 22-1631 Document: 48 Page: 11 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`11
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`improve the device’s calculation of the user’s pulse.” See,
`e.g., ’1520 Decision at *20.
`The Board therefore did not fail to consider evidence or
`argument. Rather, it considered all of Masimo’s points; it
`just did not reach the conclusions that Masimo desired.
`III
` Masimo argues that the Board erred in relying on Ap-
`ple’s greatest curvature theory as a motivation to combine
`because it was allegedly included for the first time in Ap-
`ple’s Reply.8 All arguments must be included in the peti-
`tion. VLSI Tech. LLC v. Intel Corp., 53 F.4th 646, 654 (Fed.
`Cir. 2022) (“[T]he petition defines the scope of the IPR pro-
`ceeding and [] the Board must base its decision on argu-
`ments that were advanced by a party and to which the
`opposing party was given a chance to respond.”). However,
`a party is “not barred from elaborating on [its] arguments
`on issues previously raised.” Chamberlain Grp., Inc. v. One
`World Techs., Inc., 944 F.3d 919, 925 (Fed. Cir. 2019). That
`type of elaboration is particularly permissible when it re-
`buts arguments raised by the other party. See, e.g., Provi-
`sur Techs., Inc. v. Weber, Inc., 50 F.4th 117, 122 (Fed. Cir.
`2022) (finding the petitioner’s reply proper when it was “di-
`rectly responsive” to the patent owner’s arguments).
` We review the Board’s decisions regarding the scope of
`proper reply material for an abuse of discretion. Ericsson
`Inc. v. Intell. Ventures I LLC, 901 F.3d 1374, 1379 (Fed.
`
`8 Masimo additionally points to a number of other
`theories it alleges Apple pursued without including them
`in its petitions, Appellant Br. at 33–34, but only mentions
`these in passing. We do not consider arguments that are
`not fully developed. See, e.g., Monsanto Co. v. Scruggs, 459
`F.3d 1328, 1341 (Fed. Cir. 2006) (“In order for this court to
`reach the merits of an issue on appeal, it must be ade-
`quately developed.”).
`
`

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`MASIMO CORPORATION v. APPLE INC.
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`Cir. 2018). The Board abuses its discretion if its decision:
`“(1) is clearly unreasonable, arbitrary, or fanciful; (2) is
`based on an erroneous conclusion of law; (3) rests on clearly
`erroneous fact finding; or (4) involves a record that contains
`no evidence on which the Board could rationally base its
`decision.” Intelligent Bio-Sys., Inc. v. Illumina Cambridge
`Ltd., 821 F.3d 1359, 1367 (Fed. Cir. 2016).
`
`The Board did not abuse its direction in considering the
`greatest curvature theory. Apple’s petitions and its initial
`expert declarations stated and explained that the proposed
`combination would increase light-gathering. J.A. 1896–99;
`J.A. 3053–54, ¶¶ 95–97. Its expert’s reply declarations
`merely further expanded on that theory and rebutted
`Masimo’s arguments that light gathering would only in-
`crease at the center of the sensor. Pat. Owner Resp. at 15–
`40, J.A. 2212–37; J.A. 4531–42, ¶¶ 8–23. The Board there-
`fore did not abuse its discretion in relying on that theory.
`IV
`Masimo argues that factual findings underlying the
`Board’s ultimate conclusion of obviousness are not sup-
`ported by substantial evidence. The ultimate conclusion of
`obviousness is a legal determination based on underlying
`factual findings, including whether or not a relevant arti-
`san would have had a motivation to combine references in
`the manner required to achieve the claimed invention.
`Henny Penny Corp. v. Frymaster LLC, 938 F.3d 1324, 1331
`(Fed. Cir. 2019) (citing Wyers v. Master Lock Co., 616 F.3d
`1231, 1238–39 (Fed. Cir. 2010)). We review the Board’s ob-
`viousness determination de novo, but its factual findings
`for substantial evidence. E.g., Game & Tech. Co. v. War-
`gaming Grp. Ltd., 942 F.3d 1343, 1348 (Fed. Cir. 2019).
`Substantial evidence exists when, reviewing the record as
`a whole, “a reasonable fact finder could have arrived at” the
`finding on review. In re Gartside, 203 F.3d 1305, 1312
`(Fed. Cir. 2000).
`
`

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`MASIMO CORPORATION v. APPLE INC.
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`13
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`Masimo makes a number of arguments against obvi-
`ousness, but focuses on the Board’s findings regarding (a)
`motivation to combine, (b) reasonable expectation of suc-
`cess, (c) the obviousness of ’265 patent claims 12 and 14,
`which require a reduction in the “mean path length” of
`light, (d) whether or not the Aizawa-Inokawa combination
`discloses all the claim elements, and (e) the obviousness of
`’554 patent claims 11, 17, and 28 and ’765 patent claims 12,
`18, and 29 that recite specific protrusion height ranges. We
`address each of those arguments below.
`A
`First, Masimo challenges all of the motivations to com-
`bine found by the Board. See, supra, Background.
` Many of Masimo’s arguments regarding motivation to
`combine attack the Board’s reliance on the greatest curva-
`ture theory, which provides support for improved light col-
`lection in certain of Apple’s asserted combinations.
`However, that is not the sole basis for the Board’s finding
`of a motivation to combine in any one IPR or for any one
`combination. Rather, the Board relies on multiple motiva-
`tions to combine or a more generalized finding that the
`combination would improve light collection. As counsel for
`Apple stated at oral argument, even were we to find the
`greatest curvature theory problematic, we could still affirm
`the Board’s finding. See Oral Arg. at 17:33–18:41.
`Apple’s asserted motivation of improved light collection
`rested on the premise that the nature of light itself would
`cause a convex lens to increase light gathering. The great-
`est curvature theory was simply a rebuttal to Masimo’s ar-
`gument that light would not be directed to the peripherally
`positioned detectors. See, e.g., id. The Board’s analysis in
`its decisions confirm that understanding. For example, in
`the ’1520 IPR, the Board pointed to an annotated version
`of Inokawa Figure 2 created by Apple’s expert that showed
`“the various directions that light rays may be directed,”
`creating “backscattered light that is diffuse, rather than
`
`

`

`Case: 22-1631 Document: 48 Page: 14 Filed: 09/12/2023
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`14
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`MASIMO CORPORATION v. APPLE INC.
`
`collimated, in nature.” ’1520 Decision at *20. The Board
`found that that “suggests that a lens might be useful to in-
`crease the amount of collected light and thereby increase
`the reliability of the pulse data generated using the col-
`lected light.” Id. The Board further found that Inokawa
`further supported that theory:
`[I]n a general sense, Inokawa demonstrates that it
`was known in the art prior to the ’265 patent to use
`a lens to focus diffuse light reflected from body tissue
`on to the light detecting elements of a wrist-worn
`pulse sensor, to increase the light gathered by the
`sensor and thereby improve the device’s calculation
`of the user's pulse. Inokawa also discloses, in its Fig-
`ure 2, that a convexly protruding lens may advanta-
`geously be used for this purpose.
`Id. Those findings, and Inokawa’s teachings, are distinct
`from the greatest curvature theory. Indeed, neither party
`asserts that Inokawa discusses the greatest curvature the-
`ory. See, e.g., Appellant Br. at 40. That the Board found
`that the greatest curvature theory provided additional
`support for improved light capture as a motivation does not
`impact whether the Board had evidentiary support for its
`conclusion that “a lens might be useful to increase the
`amount of collected light and thereby increase the reliabil-
`ity of the pulse data generated using the collected light.”
`’1520 Decision at *20. And, given Apple’s expert testimony
`and Inokawa, we conclude that finding was supported by
`substantial evidence. We therefore do not need to reach
`the more specific issue whether the greatest curvature the-
`ory is supported by substantial evidence.
` We further conclude that, in certain IPRs, protection of
`the sensor elements provides an alternative or additional
`motivation to combine. Masimo argues that a convex cover
`provides no more protection than a flat cover, and that a
`convex cover would be more prone to scratches, making it
`undesirable. But the Board already found that a convex
`
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`Case: 22-1631 Document: 48 Page: 15 Filed: 09/12/2023
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`MASIMO CORPORATION v. APPLE INC.
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`15
`
`cover would protect sensor elements, which was not dis-
`puted by Masimo, and that the potential for scratches was
`but one tradeoff that a person of ordinary skill in the art
`would consider. ’1537 Decision at *24–25 (citing Oral
`Hearing Tr. at 64:6–65:5). Masimo’s arguments that that
`motivation is not supported by substantial evidence there-
`fore largely amount to asking us to reweigh the evidence
`already considered by the Board, which we decline to do.
`“A finding is supported by substantial evidence if a reason-
`able mind might accept the evidence as adequate to sup-
`port the finding.” Henny Penny Corp. v. Frymaster, LLC,
`938 F.3d 1324, 1330 (Fed. Cir. 2019). The Board’s determi-
`nations that protection provided a motivation to combine
`was thus supported by substantial evidence.
`
`Because we conclude that the Board’s findings regard-
`ing improved light collection and protection of sensor ele-
`ments were supported by substantial evidence, we do not
`need to consider the issues of adhesion and the related ben-
`efit of improved detection efficiency.
`B
`In addition to challenging the Board’s findings on mo-
`
`tivation to combine, Masimo asserts that the Board’s find-
`ings that there would have been a reasonable expectation
`of success were not supported by substantial evidence. Its
`main argument is that the Board ignored Apple’s expert
`testimony regarding the complexity of designing a physio-
`logical sensor. See, e.g., Appellant Br. at 53–56, 68, 78–79.
`However, much of the complexity that Masimo points to is
`tied to specific goals, such as improving light collection, and
`perfecting the sensor structure. The claims themselves re-
`quire no specific benefits. Rather, they simply require a
`noninvasive optical physiological sensor comprising cer-
`tain elements. Apple only needed to show that a person of
`ordinary skill in the art would have had a reasonable ex-
`pectation of success in arriving at the claimed invention,
`not an ideal optical sensor. E.g., Intelligent Bio-Sys, Inc.,
`
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`Case: 22-1631 Document: 48 Page: 16 Filed: 09/12/2023
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`16
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`MASIMO CORPORATION v. APPLE INC.
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`821 F.3d at 1367 (“The reasonable expectation of success
`requirement refers to the likelihood of success in combining
`references to meet the limitations of the claimed inven-
`tion.”). Masimo’s arguments regarding reasonable expec-
`tations of success are therefore without merit.
`C
` Masimo separately argues that the Board’s findings re-
`garding the obviousness of ’265 patent claims 12 and 14,
`which require a reduction in the “mean path length” of
`light are not supported by substantial evidence. Apple’s
`support for the alleged disclosure of a reduction of mean
`path length rests on the theory that, with a convex lens,
`“refraction of the incoming reflected light can shorten the
`path of the light before it reaches the detector . . . because
`the incoming light is ‘condensed’ toward the center.” J.A.
`3068–70, ¶¶ 119–20. According to Masimo, that theory
`contradicts the greatest curvature theory, which assumes
`that light is concentrated at the detectors. Masimo argues
`that the Board’s findings for the mean path length claims,
`relying on Apple’s expert testimony that light condenses
`toward the center, therefore contradict its findings on the
`greatest curvature theory. See ’1536 Decision at *18.
`Masimo also criticizes the Board for relying on Apple’s ex-
`pert’s analysis of a single ray of light, rather than requiring
`an analysis of the aggregate effect on all light that travels
`through the convex surface or calculation of an average.
`
`Apple responds that Masimo forfeited any argument
`that dependent claims 12 and 14 of the ’265 patent were
`separately patentable by not arguing them before the
`Board. Apple also points to testimony and illustrations
`from its expert showing that the lens would concentrate
`light and reduce the mean path length, demonstrating that
`the Board’s finding was supported by substantial evidence.
`
`To the extent Masimo is making new criticisms of Ap-
`ple’s expert testimony (e.g., that he analyzed a single ray of
`light rather than the aggregate), we agree with Apple that
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`MASIMO CORPORATION v. APPLE INC.
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`17
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`those arguments should have been raised before the Board.
`However, Masimo could not have earlier argued that the
`Board’s findings were contradictory. We therefore do not
`determine that argument to be forfeited, despite Masimo’s
`previous decision to not separately argue for the independ-
`ent claims’ patentability.
` Nonetheless, we do not agree with Masimo on the mer-
`its. Although there may be tension between certain por-
`tions of testimony of Apple’s expert that the Board relied
`on, we do not observe a clear contradiction negating a find-
`ing of substantial evidence. That the greatest curvature
`theory may support increased light collection at the detec-
`tors is not incongruent with light being condensed toward
`the center. Those two theories are not mutually exclusive.
`See, e.g., ’1521 Decision at *20 (“[T]he light-focusing prop-
`erties of a convex lens . . . does not demonstrate ‘that a con-
`vex lens directs all light to the center.’”); Oral Arg. at
`15:10–20 (“Now, that motivation to combine does not focus
`on any sort of theory that all light must go to the dead cen-
`ter in a convex lens.”). The Board’s finding that light being
`condensed toward the center does not mean all light is con-
`centrated at a single point to the exclusion of light else-
`where is supported by substantial evidence. ’1521 Decision
`at *24 (“[I]t is reasonable to conclude, as Dr. Kenny does,
`that the central light lost by adding a protrusion will be
`outweighed by the peripheral light gained by adding a pro-
`trusion.”). The Board’s findings regarding claims 12 and
`14 of the ’265 patent were therefore supported by substan-
`tial evidence.
`
`D
` Masimo argues that the Aizawa-Inokawa combination
`in the ’1520 and ’1521 IPRs does not disclose all the re-
`quired