Plastipak Packaging, Inc. v. Premium Waters, Inc.

Case: 21-2244    Document: 49    Page: 1   Filed: 12/19/2022




   United States Court of Appeals
       for the Federal Circuit
                  ______________________

           PLASTIPAK PACKAGING, INC.,
                 Plaintiff-Appellant

                            v.

                PREMIUM WATERS, INC.,
                    Defendant-Appellee
                  ______________________

                        2021-2244
                  ______________________

    Appeal from the United States District Court for the
 Western District of Wisconsin in No. 3:20-cv-00098-wmc,
 Judge William M. Conley.
                 ______________________

                Decided: December 19, 2022
                  ______________________

     CHRISTOPHER ROBERT DILLON, Fish & Richardson P.C.,
 Boston, MA, argued for plaintiff-appellant. Also repre-
 sented by WHITNEY REICHEL; AHMED JAMAL DAVIS,
 CHRISTOPHER DRYER, Washington, DC; OLIVER RICHARDS,
 San Diego, CA.

    JEFFREY COSTAKOS, Foley & Lardner LLP, Milwaukee,
 WI, argued for defendant-appellee. Also represented by
 KIMBERLY KRISTIN DODD, SARAH ELIZABETH RIEGER;
 DANIEL FLAHERTY, ANDREW GROSS, Chicago, IL.
                 ______________________
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 2         PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



     Before NEWMAN, STOLL, and STARK, Circuit Judges.
 STARK, Circuit Judge.
     In this patent case, the District Court granted sum-
 mary judgment in favor of Defendant-Appellee Premium
 Waters, Inc. (“Premium Waters”), finding that Plaintiff-
 Appellant Plastipak Packaging, Inc.’s (“Plastipak”) twelve
 patents-in-suit were invalid for nonjoinder under pre-AIA
 

(f) (2006). 1 On appeal, the parties dispute
 whether summary judgment was proper. We reverse and
 remand.
                               I
                              A
      Plastipak owns U.S. Patent Nos. 8,857,637; 9,033,168;
 9,139,326; 9,403,310; 9,522,759; 9,738,409; 9,850,019;
 10,023,345; 10,214,311; 10,214,312; 10,266,299; and
 10,457,437.2 Each patent is entitled “Lightweight Plastic
 Container and Preform” and claims priority to U.S. Appli-
 cation No. 11/749,501, filed on May 16, 2007, which was a
 continuation-in-part of U.S. Application No. 11/368,860,
 filed on March 6, 2006. Each patent lists Richard C. Darr
 and Edward V. Morgan as inventors.




     1   AIA refers to the Leahy-Smith America Invents
 Act, 

 Stat. 284 (2011). Because the
 application that led to the patents-in-suit never contained
 a claim having an effective filing date on or after March 16,
 2013, or a reference under 

, 121, or 365(c)
 to any patent or application that ever contained such a
 claim, pre-AIA law applies. See AIA § 3(n)(1), 125 Stat. at
 293.
      2  Each patent or patent application will be referred
 to by the last three digits of its patent or application num-
 ber.
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.          3



     All twelve patents-in-suit generally concern plastic
 containers and plastic container preforms with a neck por-
 tion (also called a neck finish).3 The neck portion contains
 threads for screwing on or off a closure (e.g., a bottle cap);
 a continuous or discontinuous tamper-evident formation
 (“TEF”) to show that the bottle has been opened; and a sup-
 port flange (also called a support ring) to facilitate handling
 during manufacturing.
     One view of such a bottle is found in Figure 1 of the
 ’637 patent:




     3    We follow the parties’ and District Court’s conven-
 tion of referring to the “containers” with which the patents
 are concerned as bottles. “Preforms” become fully formed
 plastic bottles during the manufacturing process.
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 4        PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 J.A. 41. The neck portion (16) includes a support flange
 (18) with an upper surface (20) and a lower surface (22).
      A close-up view of a neck portion is shown in Figure 6
 of the ’637 patent (annotated by the parties with the names
 of the numbered features):




 J.A. 5305. The TEF (28) in this Figure 6 embodiment is
 discontinuous; that is, there are multiple TEFs rather than
 a single, continuous formation.4




     4    The patents and parties use the singular and plu-
 ral terms “TEF” and “TEFs” interchangeably, and we do so
 as well.
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.         5



     A cross-sectional side view of a neck portion is shown
 in Figure 5 of the ’637 patent (again annotated by the par-
 ties in accordance with the patent):




 J.A. 5305. The X dimension in Figure 5 (delineated by the
 vertical line to the far left of the diagram) represents a
 measurement of the vertical distance from the top of the
 dispensing opening/neck portion (30) to the lower surface
 of the support flange (22), including the threads and a TEF.
 Decreasing the magnitude of the X dimension can result in
 lighter weight bottles and preforms, with related economic
 and manufacturing benefits.
      The patents-in-suit can be split into two groups. Seven
 patents – the ’637, ’168, ’759, ’409, ’019, ’345, and ’312 –
 have claims reciting neck portions with an X dimension of
 0.580 inches or less. For simplicity, and following the lead
 of the parties and the District Court, we refer to this as the
 “X Dimension Limitation” and this group of seven as the “X
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 6         PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 Dimension Patents.” 5 Five patents – the ’326, ’310, ’311,
 ’299, and ’437 – have claims reciting a discontinuous TEF.
 We refer to this as the “Discontinuous TEF Limitation” and
 this group of five as the “Discontinuous TEF Patents.” 6
                              B
     The parties present competing stories of invention con-
 cerning Plastipak’s twelve patents. Plastipak contends
 that Darr and Morgan were the sole inventors. Premium
 Waters counters that the patents should have included a
 third co-inventor, Alessandro Falzoni, an employee of
 SACMI Imola (“SACMI”), an Italian company.
     Certain details of the process leading to the patented
 inventions are undisputed. Plastipak and Premium Wa-
 ters agree that Falzoni worked on what SACMI referred to
 as its “Multi-Lok 27” or “ML27” project. The ML27 con-
 cerned a design that included a neck portion, a specialty
 closure, and a discontinuous TEF. The parties further
 agree that over the course of several months in 2005 and
 2006, Falzoni and his SACMI colleagues interacted with



     5    To be precise, none of the patents includes claims
 literally reciting an “X dimension.” Instead, the claims re-
 cite some variation of the following language: “wherein the
 vertical distance from the dispensing opening to the lower
 surface of the support flange, including threads and the
 tamper-evident formation, is 0.580 inches or less.” J.A. 47
 (’637 patent at 7:7-10).
      6   Several of the patents-in-suit contain claims recit-
 ing a “means for indicating tampering” or “additional
 means for indicating tampering.” See, e.g., J.A. 46 (’637 pa-
 tent at 6:63-64). Before the District Court, Premium Wa-
 ters argued that these are means-plus-function claims,
 whose required structure includes a discontinuous TEF.
 See J.A. 1631 nn.6-8. Plastipak does not challenge this con-
 tention on appeal.
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.        7



 Darr and other Plastipak personnel and, during this pe-
 riod, Plastipak considered trying to obtain exclusive rights
 to SACMI’s ML27 design.
      In the course of these Plastipak-SACMI interactions,
 on June 13, 2005, Falzoni emailed Darr, stating he was
 sending Darr a file of the “3D model of the neck finish,”
 adding that “[t]he area below the neck support ring has
 been left undefined and you can change it at your ease.”
 J.A. 2331. Images of what Premium Waters contends is
 the model sent by Falzoni to Darr were reproduced in this
 litigation and are shown below:




 J.A. 5338. The model did not explicitly depict a lower sur-
 face of a support flange. Because the X Dimension Limita-
 tion is the distance between the dispensing opening and
 the lower surface of the support flange, the absence of the
 latter feature gives rise to a dispute as to whether the X
 Dimension of this 3D model can be determined. The par-
 ties further dispute whether the 3D model concerned a
 metal tool for testing closures and whether the dimensions
 of the 3D model would have been passed on to any con-
 tainer or container preform.
     On the same day he received Falzoni’s email, Darr re-
 sponded by sending back to Falzoni a file with a design that
 included a lower surface of a support flange and a 0.591-
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 8         PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 inch X Dimension. This is shown below (the X Dimension
 is again indicated by the line furthest to the left):




 J.A. 2337. In Darr’s email, he asked Falzoni to inform him
 if the dimensions were acceptable. In response, Falzoni
 stated that he had examined the file from Darr, did not of-
 fer any corrections, and added “everything looks right.”
 J.A. 2333.
     Plastipak and SACMI continued communicating about
 the ML27 design, including by Darr providing designs to
 SACMI with increasingly large X Dimensions, of 0.631
 inches and 0.641 inches. Meanwhile, in November 2005,
 an internal SACMI presentation on the ML27 project
 touted its shorter neck portion and included an embodi-
 ment with an X Dimension of roughly 0.5787 inches (i.e.,
 less than 0.580 inches). However, it appears Falzoni did
 not share this document with its smaller X Dimension with
 Plastipak during the relevant time. Eventually, in early
 2006, the discussions between Plastipak and SACMI broke
 down. In March 2006, Darr and Morgan filed the patent
 application that eventually resulted in the patents at issue.
                              C
     In January 2020, Plastipak sued Premium Waters in
 the United States District Court for the Western District of
 Wisconsin for infringement of various claims of its twelve
 patents. As part of discovery, Falzoni testified in a video
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.         9



 deposition about his June 2005 email. During the deposi-
 tion, Falzoni opened a file containing a 3D model that had
 purportedly been attached to his original email. Falzoni
 then measured the neck finish in that model, testifying it
 had an X Dimension of approximately 0.563 inches, based
 on what Falzoni identified as the end of the support ring.
 When questioned about the X Dimension, Falzoni stated:
 “There was just a reasonable indication of where it should
 – it should be, but since it – there wasn’t the lower surface,
 we cannot say that there was the unmistakabl[e] surface
 height.” J.A. 744.
     The parties dispute whether Falzoni’s testimony sup-
 ports Premium Waters’ position that Falzoni is a co-inven-
 tor based on his contribution to the X Dimension
 Limitation. The 3D model also included a discontinuous
 TEF, another feature Premium Waters asserted entitles
 Falzoni to co-inventor status, though the parties do not
 agree on whether Falzoni contributed anything more than
 the state of the art.
      Premium Waters eventually moved for summary judg-
 ment of invalidity, asserting that the patents were invalid
 for failure to include Falzoni as a joint inventor, because he
 contributed the X Dimension Limitation and the Discontin-
 uous TEF Limitation. The District Court granted Pre-
 mium Waters’ motion and entered final judgment in favor
 of Premium Waters.
     In explaining the bases for its decisions, the District
 Court stated that Falzoni was “at least” a joint inventor of
 “the patented invention” because he had disclosed to Darr
 a neck finish measuring less than 0.580 inches with a dis-
 continuous TEF. J.A. 28. The Court noted that although
 the image of the 3D model lacked a lower surface of a sup-
 port flange, the image constituted clear and convincing ev-
 idence of Falzoni’s disclosure, leaving “no doubt” that the
 image “contributed significantly to the conception of a com-
 plete neck finish.” J.A. 28. The Court further observed
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 10         PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 that, even if the image were of a metal testing tool (and not
 of a bottle or preform), the dimensions – including the X
 Dimension – of that tool would be carried through to a plas-
 tic preform made from the tool. [J.A. 28 n.17, J.A. 25 (“In
 other words, a preform created by this tool would
 have the same X dimension as that of the tool.”)] Fi-
 nally, and “ultimately controlling” in its view, the District
 Court found the record was
      robust in demonstrating the further collaboration
      between Falzoni and Darr in arriving at the essen-
      tial invention. Indeed, the same day that Falzoni
      sent Darr the 3D image, Darr responded with two
      emails describing his reaction to the 3D image and
      creation of drawings based on it. The cherry on top
      for this court, and it is confident for any reasonable
      jury, is that any potential business relationship be-
      tween Plastipak and SACMI with respect to joint
      use of the ML27 design fell apart in March 2006,
      the same month that the ’860 application was filed,
      calling into question any basis for Darr claiming an
      honest mistake in failing to name Falzoni as an in-
      ventor.
 J.A. 28-29.
    Plastipak timely appealed. We have jurisdiction under
 

(a)(1).
                               II
     “In patent appeals, we apply the law of the regional cir-
 cuit to which district court appeals normally lie, unless the
 issue pertains to or is unique to patent law.” AbbVie
 Deutschland GmbH & Co., KG v. Janssen Biotech, Inc., 

 (Fed. Cir. 2014) (internal quotation marks
 omitted). Here, following Seventh Circuit law, we review
 the District Court’s grant of summary judgment de novo.
 See, e.g., Wis. Alumni Rsch. Found. v. Apple Inc., 

 (Fed. Cir. 2018) (applying Seventh Circuit law).
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.         11



 We construe all facts and draw all reasonable inferences in
 the light most favorable to the nonmoving party. See 

      Summary judgment is proper “‘if the movant shows
 there is no genuine dispute as to any material fact and the
 movant is entitled to judgment as a matter of law.’” Austin
 v. Walgreen Co., 

 (7th Cir. 2018) (quot-
 ing Fed. R. Civ. P. 56(a)). We do not “‘weigh the evidence’
 or ‘determine the truth of the matter’” but “merely ‘deter-
 mine whether there is a genuine issue for trial.’” 

 (quot-
 ing Anderson v. Liberty Lobby, Inc., 

 (1986)).
      “A factual dispute is genuine only if ‘the evidence is
 such that a reasonable jury could return a verdict for the
 nonmoving party.’” Alston v. City of Madison, 

 (7th Cir. 2017) (quoting Anderson, 

). A factual dispute is material, rather than irrelevant,
 if, based on the underlying substantive law, it is probative
 of what a party must prove in order to prevail on its claim.
 See Carroll v. Lynch, 

 (7th Cir. 2012).
     The substantive law pertinent to the dispute before us
 is the law governing inventorship. Applicable here is the
 pre-AIA version of 

(f), which provides: “A
 person shall be entitled to a patent unless . . . he did not
 himself invent the subject matter sought to be patented.”
 Inventorship presents a question of law which may be pred-
 icated on underlying factual findings. See Ethicon, Inc. v.
 U.S. Surgical Corp., 

 (Fed. Cir. 1998).
     To be a joint inventor, one must:
     (1) contribute in some significant manner to the
     conception or reduction to practice of the invention,
     (2) make a contribution to the claimed invention
     that is not insignificant in quality, when that con-
     tribution is measured against the dimension of the
     full invention, and (3) do more than merely explain
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 12        PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



      to the real inventors well-known concepts and/or
      the current state of the art.
 Pannu v. Iolab Corp., 

 (Fed. Cir. 1998).
 Where these requisites are satisfied but a patent fails to
 name the joint inventor, that patent may be invalid for non-
 joinder. See 

.7 While inventorship is evalu-
 ated on a claim-by-claim basis, the failure to join an
 inventor of any claim invalidates the entire patent. See
 Egenera, Inc. v. Cisco Sys., Inc., 

, 1376 (Fed.
 Cir. 2020); Trovan, Ltd. v. Sokymat SA, Irori, 

 (Fed. Cir. 2002); Ethicon, 

.
     “[A] moving party seeking to invalidate a patent at
 summary judgment must submit such clear and convincing
 evidence of facts underlying invalidity that no reasonable
 jury could find otherwise.” SRAM Corp. v. AD-II Eng’g,
 Inc., 

 (Fed. Cir. 2006). In connection
 with assertions of joint inventorship, meeting that stand-
 ard requires alleged joint inventors to “prove their contri-
 bution to the conception with more than their own
 testimony concerning the relevant facts.” Gemstar-TV
 Guide Int’l, Inc. v. Int’l Trade Comm’n, 

 (Fed. Cir. 2004). Whether an alleged joint investor’s “tes-
 timony has been sufficiently corroborated is evaluated un-
 der a ‘rule of reason analysis,’ which requires that an
 evaluation of all pertinent evidence must be made so that
 a sound determination of the credibility of the inventor’s
 story may be reached.” 

 (internal quotation marks omit-
 ted).



      7  Some mistakes in inventorship can be corrected,
 saving the validity of the patent. See 

.
 Given our disposition, which will require further proceed-
 ings with respect to validity, we do not reach the parties’
 dispute as to whether Plastipak is entitled to correct its pa-
 tents.
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.        13



      The first step in assessing inventorship is ordinarily
 claim construction, in order to determine the scope of a
 claim’s subject matter. See Trovan, 

.
 Where, as here, the parties do not dispute the scope of any
 particular claim term, however, claim construction is not
 necessary. See O2 Micro Int’l Ltd. v. Beyond Innovation
 Tech. Co., 

 (Fed. Cir. 2008); see also
 In re VerHoef, 

 (Fed. Cir. 2018) (analyzing
 joint inventorship without mentioning claim construction).
 Instead, the disputes before us are whether, applying the
 summary judgment standard, a reasonable factfinder could
 fail to find that Falzoni was a co-inventor of the X Dimen-
 sion Patents and Discontinuous TEF Patents. As ex-
 plained below, we conclude that a reasonable factfinder,
 taking the evidence in the light most favorable to Plastipak
 as the nonmoving party, could reject Premium Waters’ po-
 sition on both of these points. Accordingly, we find these
 matters present genuine disputes of material fact and sum-
 mary judgment is not warranted.
                               III
                               A
     Summary judgment was improper with respect to the
 X Dimension Patents; that is, those that claim a neck por-
 tion measuring 0.580 inches or less from a dispensing open-
 ing to a lower surface of a support flange. The District
 Court found that “Falzoni was at least a joint inventor of
 the patented invention, having initially disclosed to Darr a
 design of a neck finish measuring less than 0.580 inches.”
 J.A. 28. To invalidate the relevant patents on summary
 judgment, Premium Waters had to present evidence from
 which all reasonable finders of fact, taking the evidence in
 the light most favorable to Plastipak, would have to con-
 clude that Falzoni actually contributed in a legally suffi-
 cient manner to the invention. See, e.g., Trovan, 

. The record reflects a genuine dispute of material
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 14        PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 fact as to whether Falzoni sufficiently contributed to the X
 Dimension Limitation.
     Premium Waters’ principal support for its position is
 the June 2005 email Falzoni sent to Darr, which appears
 to have attached the 3D model. In the email, Falzoni stated
 that the model was of a neck portion with a neck support
 ring, which Premium Waters asserts “necessarily includes
 a lower surface.” Response Br. 41. As the District Court
 recognized, however, the 3D model did not expressly dis-
 close a lower surface of a support flange. [See J.A. 11, 28.]
 While Falzoni testified in his deposition that he knew
 where the lower surface was and also that he could meas-
 ure the X Dimension – and did so during his deposition,
 finding it was approximately 0.563 inches, meeting the
 claim limitation of being less than 0.580 inches – each of
 these propositions was highly contested by Plastipak,
 which presented evidence from which a reasonable fact-
 finder could reach conclusions contrary to those proposed
 by Premium Waters.
     For example, Plastipak points to portions of Falzoni’s
 testimony in which he acknowledged uncertainty about the
 exact measurement of the X Dimension in the 3D model.
 Falzoni testified: “There was just a reasonable indication
 where it should – it should be, but since it – there wasn’t
 the lower surface, we cannot say that there was the unmis-
 takabl[e] surface height.” J.A. 744. Plastipak also pre-
 sented testimony from its expert, Ottmar Brandau, who
 opined that the 3D model did not contain any support
 flange, did not depict a preform or bottle, and did not, in
 his expert view, show an X Dimension of 0.580 inches or
 less. Moreover, there was evidence that the 3D model con-
 cerned a tool for testing closures and not for manufacturing
 bottles or preforms, which – if credited – could undermine
 the weight a reasonable factfinder would place on the 3D
 model.
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.       15



      Plastipak also introduced evidence from which a rea-
 sonable factfinder could find that Darr and Morgan con-
 ceived of their inventions entirely independently of any
 work on which Darr and Falzoni had collaborated. There
 is, for example, evidence that Plastipak’s claims originated
 with Morgan in January 2006 and that Morgan personally
 derived the 0.580-inch X Dimension based on measure-
 ments he took of human thumbs. The record could likewise
 support a finding that Falzoni contributed nothing to the X
 Dimension Limitation. It contains evidence that: Darr sub-
 mitted designs to Falzoni of neck portions with X Dimen-
 sions greater than 0.580 inches – initially 0.591 inches and
 later increasing to 0.641 inches – without objection from
 Falzoni; Falzoni believed Darr was best suited to choose
 the thickness of the support flange, which would neces-
 sarily affect the height of the X Dimension; and Figure 6,
 on which Premium Waters relies as a purported embodi-
 ment of all twelve patents-in-suit, may have been con-
 ceived of and resulted from work by Darr, not Falzoni.
      Ultimately, we agree with Premium Waters that it pre-
 sented sufficient evidence from which a reasonable fact-
 finder may find clear and convincing evidence that Falzoni
 was a joint inventor of the X Dimension Patents. Such a
 finding could be grounded in Falzoni’s testimony, as cor-
 roborated by the 3D model and the testimony of another
 SACMI employee, as well as the arguably suspicious time-
 line, in which the collapse of Plastipak’s efforts to license
 SACMI’s ML27 design was quickly followed by Darr and
 Morgan filing their patent application. Such a finding
 could lead to the conclusion that the X Dimension Patents
 are invalid for failure to name Falzoni as an inventor. Cru-
 cially, however, nothing in the record requires a reasonable
 factfinder – particularly one who is resolving all fact dis-
 putes, and drawing all reasonable inferences, in
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 16        PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



 Plastipak’s favor – to make these necessary findings.8 Ac-
 cordingly, summary judgment of invalidity is not war-
 ranted.
                               B
     Summary judgment invalidating the Discontinuous
 TEF Patents is also inappropriate. With respect to these
 patents, there is, at a minimum, a genuine dispute of ma-
 terial fact as to whether Falzoni contributed anything
 other than what was already the state of the art. 9 See Nar-
 tron Corp. v. Schukra U.S.A. Inc., 

 (Fed. Cir. 2009) (providing well-known principles does not
 make one a joint inventor); Eli Lilly & Co. v Aradigm Corp.,
 

 (Fed. Cir. 2004) (“A contribution of in-
 formation in the prior art cannot give rise to joint inventor-
 ship because it is not a contribution to conception.”); see
 also In re VerHoef, 

 (reviewing for


      8   In reaching this conclusion, we have considered not
 just the evidence highlighted in the body of this opinion,
 but all of Premium Waters’ evidence, such as SACMI’s No-
 vember 2005 internal presentation, and similarities be-
 tween the figures in the patents and the ’860 patent
 application, on the one hand, and 2D images created by
 Premium Waters based on Falzoni’s purported 3D model,
 on the other. Whether the evidence is considered individ-
 ually or in totality, it does not require a reasonable fact-
 finder to find that Falzoni is a co-inventor of the X
 Dimension Patents.
     9    We address these issues with respect to just five of
 the patents-in-suit, as this is how the parties have pre-
 sented the issue on appeal. In the District Court, Premium
 Waters sought summary judgment of invalidity with re-
 spect to eleven of the twelve Plastipak patents – all but the
 ’312 patent – on the basis of Falzoni’s purported contribu-
 tion to the Discontinuous TEF Limitation. [See J.A. 1630-
 31]
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.       17



 substantial evidence Patent Trial and Appeal Board’s de-
 termination that feature of invention was not well-known
 in art).
     Plastipak marshaled evidence from which a reasonable
 factfinder, and particularly one viewing the evidence in the
 light most favorable to Plastipak, could find that a discon-
 tinuous TEF was well-known and constituted the state of
 the art, and, therefore, Falzoni’s contribution of a discon-
 tinuous TEF was not sufficient to justify joint inventorship.
 This evidence included several prior art patents which
 might be read as disclosing a discontinuous TEF – which is
 how the Examiner evaluating Plastipak’s applications read
 at least one of them – as well as statements made by Fal-
 zoni.10 Premium Waters disputes all this, based, in part,
 on its interpretation of testimony from Plastipak’s expert.
 All of this demonstrates there is a genuine dispute as to the
 material fact of whether Falzoni’s purported contribution
 was merely the state of the art. See Nartron, 

 (state of art is factual question); Pannu, 

 (state of art is material fact in evaluating nonjoin-
 der). Even the District Court recognized that “[t]he parties
 dispute whether the use of a [TEF] that is discontinuous,
 viewed in isolation, is another novel aspect of the patents-
 in-suit.” J.A. 6 n.5. Resolution of this fact dispute is nec-
 essary in order to determine whether Falzoni was a joint
 inventor and, thus, whether the patents are invalid for
 nonjoinder. Accordingly, summary judgment of invalidity
 of the Discontinuous TEF Patents is not proper.




     10   The parties dispute whether Falzoni’s purported
 statements are inadmissible hearsay. We need not reach
 this issue because Plastipak’s other evidence was sufficient
 to create a genuine dispute of material fact precluding
 summary judgment. See Haugerud v. Amery Sch. Dist.,
 

, 691 n.3 (7th Cir. 2001).
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 18        PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



                               C
      The District Court concluded that any reasonable fact-
 finder would have to side with Premium Waters on these
 disputed facts. We disagree. Although the District Court
 may be correct that Premium Waters presented an “over-
 whelming” amount of evidence, J.A. 1, that does not mean
 Plastipak presented an insufficient amount of evidence
 from which a reasonable factfinder could find, instead, that
 Falzoni was not a joint inventor. Moreover, while the Dis-
 trict Court may have been understandably skeptical of
 Plastipak – based on the apparent tension between Darr’s
 testimony that he was unaware in 2005 of others’ efforts to
 develop lightweight neck finishes and the subsequent pro-
 duction, by Premium Waters, of the SACMI evidence,
 which Plastipak had “failed to disclose timely” and “effec-
 tively (if not intentionally) hid[],” J.A. 15-20, 30 n.18 – the
 SACMI evidence did not erase from the record Plastipak’s
 evidence of its alleged independent invention. Just be-
 cause Plastipak’s witnesses, in the words of Premium Wa-
 ters, “professed no recollection” of the SACMI evidence
 does not render that evidence “essentially uncontroverted,”
 as Premium Waters wrongly states. Response Br. 2. A
 factfinder, not the trial court at summary judgment, will
 need to weigh all of the competing evidence and draw its
 own reasonable conclusions as to inventorship. See gener-
 ally Runkel v. City of Springfield, 

, 741-42 (7th
 Cir. 2022).
     While we have stated that “[c]onception is the touch-
 stone of inventorship,” Burroughs Wellcome Co. v. Barr
 Labs., Inc., 

 (Fed. Cir. 1994), we have
 also emphasized that “[c]ontributions to realizing an inven-
 tion may not amount to a contribution to conception if they
 merely explain what was then state of the art,” Eli Lilly,
 

 (internal quotation marks omitted). We
 have further observed that the “line between actual contri-
 butions to conception and the remaining, more prosaic con-
 tributions to the inventive process that do not render the
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 PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.       19



 contributor a co-inventor is sometimes a difficult one to
 draw.” Eli Lilly, 

.
     As this case illustrates, often the assessment of what
 contribution has been made by a purported inventor, and
 whether that contribution is significant, is bound up with
 material fact disputes which a reasonable factfinder could
 resolve in favor of either party. Here, specifically, a rea-
 sonable factfinder could find Falzoni did not provide Darr
 with the X Dimension Limitation and merely “contributed”
 the prior art concept of a Discontinuous TEF – and these
 findings would mean Falzoni is not a joint inventor. Alter-
 natively, a reasonable factfinder could find the opposite, in
 which case Falzoni should have been listed on the Plasti-
 pak patents as a joint inventor. On the record before the
 District Court, these genuine disputes of material fact were
 not amenable to resolution on summary judgment.
    Hence, again, the grant of summary judgment was not
 proper.
                               IV
    We have considered the parties’ remaining arguments
 and find them unpersuasive.
     We have not weighed the evidence nor determined the
 truth of the matters before us. Our role is to evaluate
 whether the record reveals genuine disputes of material
 fact precluding summary judgment, and we find that there
 are. Therefore, we must reverse the District Court’s grant
 of summary judgment in favor of Premium Waters and re-
 mand to that Court for further proceedings not inconsistent
 with this opinion. 11



     11  Premium Waters moved for summary judgment on
 other grounds in addition to improper inventorship, includ-
 ing indefiniteness. On remand, it will be for the District
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 20          PLASTIPAK PACKAGING, INC.   v. PREMIUM WATERS, INC.



                REVERSED AND REMANDED
                             COSTS
 No costs.




 Court to determine what motions it must now consider or
 whether, instead, the case is ready for trial.