Google LLC v. Valtrus Innovations Ltd.

Case: 24-1945 Document: 44 Page: 1 Filed: 10/19/2026 United States Court of Appeals for the Federal Circuit ______________________ GOOGLE LLC, Appellant v. VALTRUS INNOVATIONS LTD., Appellee ______________________ 2024-1945 ______________________ Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. IPR2022- 01545. ______________________ Decided: October 19, 2026 ______________________ NATHAN R. SPEED, Wolf, Greenfield & Sacks, P.C., Bos- ton, MA, argued for appellant. Also represented by JOHN W. CUSTER, RICHARD F. GIUNTA, ADAM R. WICHMAN. PHILIP J. WARRICK, Irell & Manella LLP, Washington, DC, argued for appellee. Also represented by JONATHAN M. LINDSAY, Newport Beach, CA; JASON SHEASBY, HONG ANNITA ZHONG, Los Angeles, CA; AMY E. PROCTOR, Sullivan & Cromwell LLP, Los Angeles, CA. ______________________ Case: 24-1945 Document: 44 Page: 2 Filed: 10/19/2026 2 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. Before HUGHES and CUNNINGHAM, Circuit Judges, and BURROUGHS, District Judge. 1 CUNNINGHAM, Circuit Judge. Google LLC (“Google”) appeals a Final Written Deci- sion of the Patent Trial and Appeal Board in IPR2022-01545 regarding U.S. Patent No. 6,728,704 (“the ’704 patent”). J.A. 1–44 (“Decision”). The Board deter- mined that Google did not demonstrate that any of claims 1–23 of the ’704 patent are unpatentable. Decision at 41–42. For the reasons below, we affirm. I. BACKGROUND Valtrus Innovations Ltd. (“Valtrus”) owns the ’704 pa- tent, which claims methods and computer-readable memory for merging or instructing a computer to merge search-result lists from multiple search engines. See Deci- sion at 1, 3; ’704 patent at col. 8 ll. 2–18, 43–67, col. 9 ll. 20–35, col. 10 ll. 6–25. Claim 1 of the ’704 patent is il- lustrative and recites: 1. A method of merging result lists from multiple search engines, said method comprising: transmitting a query to a set of search engines; receiving in response to said query a result list from each search engine of said set of search en- gines, each result list including one or more en- tries; selecting a subset of entries from each result list to form a set of selected entries; 1 Honorable Allison D. Burroughs, District Judge, United States District Court for the District of Massachu- setts, sitting by designation. Case: 24-1945 Document: 44 Page: 3 Filed: 10/19/2026 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. 3 assigning to each selected entry of said set of se- lected entries a scoring value according to a scoring function; assigning to each subset a representative value ac- cording to the scoring values assigned to its entries; and producing a merged list of entries in a predeter- mined manner based on the representative value assigned to each result list, wherein the representative value varies in accord- ance with predetermined manner. ’704 patent at col. 8 ll. 2–18. Google petitioned for inter partes review (“IPR”) of claims 1–23 of the ’704 patent. Decision at 2. Google as- serted four distinct grounds that Bushee 2 in combination with one or more prior art references (Voorhees 3 alone and/or with either or both of Koppel 4 and/or Tso 5) would have rendered the ’704 patent claims obvious. Decision at 2, 8, 42. Bushee was filed on July 24, 2001, approxi- mately five weeks before the application resulting in the ’704 patent was filed on August 27, 2001. Bushee at [22]; ’704 patent at [22]. Valtrus responded that the inventors conceived of the invention in the ’704 patent at an earlier date 6 than the filing date of the Bushee reference, such 2 U.S. Patent No. 6,711,569 (“Bushee”). 3 U.S. Patent No. 5,864,846 (“Voorhees”). 4 U.S. Patent No. 7,257,766 (“Koppel”). 5 U.S. Patent No. 6,385,602 (“Tso”). 6 The parties have marked the alleged conception date for the claimed invention of the ’704 patent as confi- dential. See Oral Arg. 01:08–35, https://www.cafc.uscourts .gov/oral-arguments/24-1945_03042026.mp3; see also Case: 24-1945 Document: 44 Page: 4 Filed: 10/19/2026 4 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. that Bushee is not prior art to the ’704 patent under pre- AIA 35 U.S.C. § 102(e). 7 Decision at 11–14, 22. The Board concluded that Bushee was not prior art to the ’704 patent under 35 U.S.C. § 102(e). Id. at 22. To reach this conclusion, the Board found that a declaration by co-inventor Dr. Tsaparas (the “Tsaparas Declaration”) supported an earlier conception date, along with files re- garding the original invention disclosures (the “Disclosure Documents”), and the Disclosure Documents’ original metadata (the “disclosure metadata”). Decision at 12–13, 17–20. The Board also found that the Disclosure Docu- ments and the disclosure metadata corroborated Dr. Tsaparas’s testimony for the alleged date of conception. Id. at 17–18. The Board then credited the analysis of Val- trus’s expert, Dr. Cole, in support of the conception date. Id. at 18–20. The Board “determine[d] that [Valtrus] has established a date of invention of the challenged claims be- fore Bushee’s filing date, demonstrated diligence from just prior to Bushee’s filing date until a constructive reduction to practice on August 27, 2001, and determine[d] that, on this record, Bushee is not prior art under 35 U.S.C. § 102(e).” Id. at 22. The Board ultimately concluded that Google had not demonstrated by a preponderance of the ev- idence that any of claims 1–23 of the ’704 patent are un- patentable. Id. at 41–42. Google timely appealed. We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A). Decision at 13. In any case, we do not have to identify the exact alleged conception date to resolve the issues in this appeal. 7 Because the application from which the ’704 patent issued was filed before March 16, 2013, we apply the pre- AIA version of § 102. Google LLC v. IPA Techs. Inc., 34 F.4th 1081, 1084 n.1 (Fed. Cir. 2022). Case: 24-1945 Document: 44 Page: 5 Filed: 10/19/2026 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. 5 II. STANDARD OF REVIEW “We review the Board’s legal conclusions de novo, and its factual findings for substantial evidence. A finding is supported by substantial evidence if a reasonable mind might accept the evidence as sufficient to support the find- ing.” NFC Tech., LLC v. Matal, 871 F.3d 1367, 1371 (Fed. Cir. 2017) (cleaned up). Under pre-AIA 35 U.S.C. § 102(e), “[a]n asserted prior art reference can be antedated based on a constructive reduction to practice by a showing of (1) conception prior to the filing date of the asserted ref- erence and (2) reasonably continuous diligence from just before the date the asserted reference was filed until the date that the patent owner filed its priority application.” Medtronic, Inc., v. Teleflex Life Scis. Ltd., 86 F.4th 902, 906 (Fed. Cir. 2023). “Priority, conception, and reduction to practice are questions of law which are based on subsidiary factual findings.” E.I. du Pont de Nemours & Co. v. Unifrax I LLC, 921 F.3d 1060, 1068 (Fed. Cir. 2019) (quoting Cooper v. Goldfarb, 154 F.3d 1321, 1327 (Fed. Cir. 1998)). III. DISCUSSION In this appeal, Google raises two challenges to the Board’s determination that Bushee is not prior art. Google asserts that the Board relied on “legally insufficient” evi- dence to corroborate Dr. Tsaparas’s inventor testimony of conception. Appellant’s Br. 58. Google also argues that the Board did not have substantial evidence to support the Board’s finding that the ’704 patent’s inventors exercised reasonably continuous diligence in reducing the invention to practice. Appellant’s Br. 28. We address each argument in turn. A. Google argues the Board erred in its determination that the invention claimed in the ’704 patent has an earlier conception date than the filing date of Bushee. See Appel- lant’s Br. 42–58. Specifically, Google asserts that the Case: 24-1945 Document: 44 Page: 6 Filed: 10/19/2026 6 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. Board erroneously relied on the “metadata and Disclosure Documents” for independent corroboration of the Tsaparas Declaration “because they are both entirely under Dr. Tsaparas’s control,” and therefore the Board’s factual findings regarding conception are not supported by sub- stantial evidence. Appellant’s Br. 50, 42. We disagree. “[W]hen a party seeks to prove conception through an inventor’s testimony the party must proffer evidence, in ad- dition to the inventor’s own statements and documents, corroborating the inventor’s testimony.” Apator Miitors ApS v. Kamstrup A/S, 887 F.3d 1293, 1295 (Fed. Cir. 2018) (cleaned up). “Such evidence is evaluated under ‘the rule of reason,’ whereby ‘all pertinent evidence is examined in order to determine whether the inventor’s story is cred- ible.’” Fleming v. Escort Inc., 774 F.3d 1371, 1377 (Fed. Cir. 2014) (quoting Sandt Tech., Ltd. v. Resco Metal & Plastics Corp., 264 F.3d 1344, 1350 (Fed. Cir. 2001)). “We have treated the sufficiency of corroboration as a question of fact[.]” Id. As we have explained, the corroboration requirement reflects “a concern that inventors testifying in patent in- fringement cases would be tempted to remember facts fa- vorable to their case by the lure of protecting their patent or defeating another’s patent.” Mahurkar v. C.R. Bard, Inc., 79 F.3d 1572, 1577 (Fed. Cir. 1996). “The purpose of the rule requiring corroboration is to prevent fraud.” Hahn v. Wong, 892 F.2d 1028, 1033 (Fed. Cir. 1989) (quotation marks omitted). To find the inventors conceived of the invention claimed in the ’704 patent before Bushee was filed, the Board primarily relied on three sets of documents: (1) the Tsaparas Declaration, (2) the Disclosure Documents, and (3) the disclosure metadata. Decision at 13, 15–17. The Board relied on the Tsaparas Declaration to show the in- ventors of the ’704 patent conceived of the claimed inven- tion before Bushee was filed and found the Disclosure Case: 24-1945 Document: 44 Page: 7 Filed: 10/19/2026 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. 7 Documents and the disclosure metadata provided “sepa- rate corroboration” of Dr. Tsaparas’s early conception tes- timony in the Tsaparas Declaration. Decision at 18; id. at 13, 15–17. Google argues that the Tsaparas Declaration, Disclo- sure Documents, and the disclosure metadata are Dr. Tsaparas’s “own statements and documents” and therefore are insufficiently independent from his testimony to satisfy the corroboration requirement. Appellant’s Br. 45, 45–49. We disagree. Valtrus’s disclosure metadata associated with the Dis- closure Documents corroborates the inventor testimony in the Tsaparas Declaration. The disclosure metadata is from Microsoft Word. J.A. 6554; J.A. 5681–82 (citing J.A. 6260–61 ¶¶ 4–5); see also Oral Arg. 19:50–20:30, https://www.cafc.uscourts.gov/oral-arguments/24-1945_03 042026.mp3 (discussing content of the Word document as- sociated with the disclosure metadata). Assuming without deciding the metadata’s authenticity, the disclosure metadata generated by Microsoft Word was not authored by Dr. Tsaparas. See Global Health Sols. LLC v. Selner, 148 F.4th 1363, 1374 (Fed. Cir. 2025). Microsoft Word metadata can provide independent corroboration of inven- tor statements and documents contained in Word files be- cause we have held that “metadata is independent of [an inventor’s] own statements and documents.” Id. The dis- closure metadata independently corroborates Dr. Tsapa- ras’s inventor testimony. Contrary to Google’s argument, Microsoft Word’s auto- matic generation of author and other metadata infor- mation independently corroborates Dr. Tsaparas’s testimony. The disclosure metadata is not like “unwit- nessed laboratory notebooks” or “unwitnessed emails and drawings” that “alone, cannot corroborate [the] inventor’s testimony of conception.” Apator, 887 F.3d at 1297; see also Stern v. Trs. of Columbia Univ., 434 F.3d 1375, 1378 Case: 24-1945 Document: 44 Page: 8 Filed: 10/19/2026 8 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. (Fed. Cir. 2006) (explaining “unwitnessed laboratory note- books on their own are insufficient to support [a] claim of co-inventorship”). The authorship and timestamp infor- mation provided in the disclosure metadata is consistent with the inventors’ conception date that Dr. Tsaparas iden- tified in his declaration. J.A. 6259–74; see also J.A. 2450 ¶ 41; J.A. 3249–50, at 52:23–53:12. Indeed, counsel for Google acknowledged that in a similar situation the re- quirement for independent corroboration would be satis- fied and that a human is not a required element for corroboration. Oral Arg. 19:20–20:00, https://www.cafc.us courts.gov/oral-arguments/24-1945_03042026.mp3. Taking “all pertinent evidence” into consideration, Fleming, 774 F.3d at 1377, the Board’s finding that the Disclosure Documents and the disclosure metadata provide “separate corroboration” for the statements in the Tsapa- ras Declaration is supported by substantial evidence, De- cision at 18. B. Google argues the Board lacked substantial evidence to support its finding that the ’704 patent’s inventors exer- cised diligence in the “three-week gap between August 8, 2001 and August 27, 2001.” Appellant’s Br. 34; see also id. 28–42. We disagree. In the pre-AIA first-to-invent system, a patent owner like Valtrus can swear behind, or “antedate,” another pa- tent asserted as a prior art reference, such as Bushee, un- der pre-AIA 35 U.S.C. § 102(e) by “showing conception of the claimed invention prior to the critical date and either actual reduction to practice prior to the reference’s critical date or ‘reasonably continuous diligence’ in reducing the invention to practice until its effective filing date.” Med- tronic, 86 F.4th at 905–06 (citing ATI Techs. ULC v. Iancu, 920 F.3d 1362, 1369 (Fed. Cir. 2019)). “Reasonable dili- gence must be shown throughout the entire critical period, which begins just prior to the competing reference’s Case: 24-1945 Document: 44 Page: 9 Filed: 10/19/2026 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. 9 effective date,” here, Bushee’s July 24, 2001 filing date, “and ends on the date of the invention’s reduction to prac- tice,” here, the filing date of the ’704 patent, August 27, 2001. Perfect Surgical Techs., Inc. v. Olympus Am., Inc., 841 F.3d 1004, 1007 (Fed. Cir. 2016) (citing Monsanto Co. v. Mycogen Plant Sci., Inc., 261 F.3d 1356, 1363 (Fed. Cir. 2001)). But “[a] patent owner need not prove the inventor continuously exercised reasonable diligence throughout the critical period; it must show there was reasonably continu- ous diligence.” Id. at 1009. “[T]he point of the diligence analysis,” ultimately, “is to assure that, in light of the evi- dence as a whole, ‘the invention was not abandoned or un- reasonably delayed.’” Id. (quoting Brown v. Barbacid, 436 F.3d 1376, 1379 (Fed. Cir. 2006)). “[T]here need not necessarily be evidence of activity on every single day if a satisfactory explanation is evidenced.” Monsanto, 261 F.3d at 1369. As explained above, Google only disputes the inventors’ diligence from August 8, 2001 to August 27, 2001, when the law firm filed the application. Appellant’s Br. 34 (“in- ventors were engaged in the signing process [for the patent application] between August 3, 2001 and August 8, 2001”); Appellant’s Reply Br. 1; Oral Arg. 02:40–02:49, https://www.cafc.uscourts.gov/oral-arguments/24-1945_03 042026.mp3. According to Google, the disputed period con- sists of only about “11 business days.” Oral Arg. 03:50–03:55. The Board’s diligence findings are supported by sub- stantial evidence. Dr. Tsaparas was based outside of the United States at the time (in Ontario, Canada), so his Au- gust 8, 2001 physical signature (the latest obtained of the four inventors’ signatures) on the inventor declaration re- quired some time to be returned by mail to the law firm’s California offices. J.A. 398–401, 376–78; Decision at 21. Valtrus’s expert, Dr. Cole, provided his opinion that “the applicant exercised diligence in preparing and filing the patent application issued as the ’704 patent” because it Case: 24-1945 Document: 44 Page: 10 Filed: 10/19/2026 10 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. “take[s] law firms on the order of several weeks or more” to draft and then finalize a patent application for filing. J.A. 2494–95, ¶ 55; Decision at 21; see also D’Amico v. Koike, 347 F.2d 867, 871 (CCPA 1965) (“[I]n determina- tion of diligence of attorneys and of their clerical and sten- ographic staffs,” “the law cannot presume that such people can immediately begin and expeditiously perform their du- ties as soon as work appears on their desks.”). These non- speculative facts amount to substantial evidence support of the Board’s finding that “the invention was not abandoned or unreasonably delayed,” Decision at 22 (quoting Perfect Surgical, 841 F.3d at 1009), during the approximately 11 business days at issue. Google’s reliance on In re Mulder, 716 F.2d 1542 (Fed. Cir. 1983), is misplaced. Appellant’s Br. 38–39. Google argues that the two-day period with no diligent ac- tivity sufficient for the applicant to lose his conception date in In re Mulder is analogous to the circumstances in this case. Id. But in In re Mulder, we stated that “focus[]ing on the shortness of the gap [wa]s misleading.” 716 F.2d at 1545. There, a draft U.S. patent application had been prepared for nearly three months and yet “the record show[ed] no activity of any kind in this country.” Id. (cleaned up). Here, Valtrus accounted for the entire period during which diligence is required, including the disputed period, using timestamp evidence of the inventors and a law firm office collaborating in the United States to com- plete, execute, and file the application resulting in the ’704 patent. Cf. id.; see also Arctic Cat Inc. v. GEP Power Prods., Inc., 919 F.3d 1320, 1331 (Fed. Cir. 2019) (“[D]ili- gence need not be perfectly continuous—only reasonably continuous.”). In sum, the Board’s determination that Valtrus “demonstrated diligence from just prior to Bushee’s filing date until a constructive reduction to practice on Au- gust 27, 2001,” Decision at 22, is supported by substantial evidence. Case: 24-1945 Document: 44 Page: 11 Filed: 10/19/2026 GOOGLE LLC v. VALTRUS INNOVATIONS LTD. 11 IV. CONCLUSION We have considered Google’s remaining arguments and find them unpersuasive. For the above reasons, we affirm the Board’s decision. AFFIRMED