US 5545531

I'll verify the patent details against live sources and check for any 2026 CAFC docket activity.

Let me check for litigation and any recent docket activity.

US Patent 5,545,531 — Verified Summary

I searched for the specific number 5545531 (and confirmed via Espacenet, Google Patents, FreePatentsOnline, and the USPTO Official Gazette record for the related continuation). Findings below. No CAFC 2026 docket activity for this patent was found — see the uncertainty note at the end.

Bibliographic data

Source: Espacenet biblio record for US5545531(A); Google Patents US5545531A.

Abstract (verbatim)

"Methods for concurrently processing multiple biological chip assays by providing a biological chip plate comprising a plurality of test wells, each test well having a biological chip having a molecular probe array; introducing samples into the test wells; subjecting the biological chip plate to manipulation by a fluid handling device that automatically performs steps to carry out reactions between target molecules in the samples and probes; and subjecting the biological chip plate to a biological chip plate reader that interrogates the probe arrays to detect any reactions between target molecules and probes."

Note a title/abstract asymmetry worth flagging: the title and all four granted claims are directed to making a plate/device, while the abstract and the bulk of the specification describe the concurrent assaying method. The assaying method was pursued in the continuation US 5,874,219 (app. 08/630,051, filed 1996-04-09), which is in the same family.

Independent claims in plain language

Claim 1 — Two-part assembled plate (body + wafer).

1. Provide a body with a plurality of wells that define open spaces.
2. Provide a wafer whose surface carries a plurality of probe arrays, where each array is a collection of probes, at least two of which differ, arranged in a spatially defined and physically addressable manner.
3. Attach the wafer to the body so that the probe arrays are exposed to (face into) the well spaces.
   Plain language: glue/join a multi-channel or multi-well plastic body onto a chip-bearing wafer so the wafer forms the floor of each well and each well's array sits inside its own compartment. (Fig. 4/5.)

Claim 3 — Barrier/well-forming material on the wafer.

1. Provide a wafer bearing a plurality of probe arrays (same array definition as above).
2. Apply a liquid-flow-resistant material surrounding each probe array, thereby creating test wells.
   Plain language: skip the molded body; instead put hydrophobic/wax/tape barriers directly on the wafer in the gaps between arrays, so the barriers themselves define the wells that hold liquid over each array.

Dependent claims: Claim 2 (dep. on 1) and claim 4 (dep. on 3) both merely limit the probes to DNA or RNA molecules.

Litigation / status notes

• The '531 patent was asserted in Affymetrix, Inc. v. Illumina, Inc., D. Del. Civ. A. No. 1:04-cv-00901-JJF (Unified Patents litigation record; court filings show a July 2006 Illumina summary-judgment motion on invalidity of the asserted '531 claims, and a 2006 Markman opinion, 446 F. Supp. 2d 277, construing '531 claim 1 language). That is the Delaware family-litigation hit referenced in the patent record, not a CAFC appeal of this number.
• Status is expired – lifetime with an anticipated expiration of 2015-06-07; no maintenance-fee lapse is indicated.

Uncertainty / caveats

• CAFC 2026 docket: I found no Federal Circuit docket entry or 2026 appellate activity tied to patent number 5545531. My searches returned zero results for "5545531 CAFC 2026 docket appeal," and the only litigation traces are the 2004–2007 Delaware district-court matter. I cannot confirm from the sources available whether any 2026 CAFC docket exists — treat "none found" as absence of evidence, not proof of absence. A direct PACER/CAFC docket query would be needed to be authoritative.
• The full claim text above is taken from the Google Patents claims listing ("Claims (4)"); I did not independently retrieve the printed patent's claim sheet or the USPTO PatentCenter PDF. The claim wording is consistent across the Google Patents, Espacenet, and FreePatentsOnline records I checked.
• Assignee history shows multiple transfers (Affymax Technologies N.V. → Affymetrix, Inc. → merger designations), so "assignee" depends on which date is referenced; current listed assignee is Affymetrix Inc.

I'll research litigation involving US 5,545,531 across patent-litigation sources.

Good initial results. Let me dig into the case outcome, appeals, and check for any other cases.

Let me pin down the specific outcome for the '531 patent and check for any other suits.

Litigation involving US 5,545,531 ("Methods for making a device for concurrently processing multiple biological chip assays")

Note on scope/method: I searched the Google Patents litigation data for this family, Unified Patents' Delaware case link, CourtListener, IPMall's Markman archive, patent-litigation press (GenomeWeb, PatentDocs, IBO, BioSpace, FierceBiotech) and SEC filings. I retrieved the full patent text and the D. Del. filings only in part before hitting my search-step limit, so I flag clearly below which items are confirmed and which are unverified. I did not retrieve any result tying 5,545,531 to a case number other than the one below, and I did not return results for similar-but-different numbers (e.g., 5,545,532 or 5,795,716 appear only as separate patents in the same suit).

The one known litigation asserting the '531 patent

Affymetrix, Inc. v. Illumina, Inc.

Sources confirming this case and the '531 patent's inclusion:

• USPTO/§290 Report to Commissioner in CA 04-0901 listing patent 5,545,531 as patent-in-suit: https://www.findforms.com/single_form.php/form/63424/Patent_Trademark_Report_to_Commissioner_District_Court_of_Delaware_District_Court_of_Delaware_Delaware
• BioSpace Markman announcement naming the five patents-in-suit (including 5,545,531): https://www.biospace.com/judge-issues-markman-order-in-affymetrix-santa-clara-california-litigation-with-illumina-inc
• Unified Patents litigation record for this docket (the link carried on the Google Patents page for US5545531): https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A04-cv-00901

Procedural history specific to the '531 patent:

1. Markman (claim construction): August 16, 2006 — Judge Farnan construed '531 terms including "probe array" ("a collection of probes, at least two of which are different, arranged in a spacially defined and physically addressable manner") and "arranged in a spacially defined and physically addressable manner" ("located in a particular location and capable of being addressed"). Text: https://ipmall.info/sites/default/files/hosted_resources/Markman/pdfFiles/2006.08.16_1_AFFYMETRIX_INC_v._ILLUMINA.pdf and https://www.courtlistener.com/opinion/[2315392](/patent/2315392)/affymetrix-inc-v-illumina-inc/

2. Illumina's summary-judgment motion of invalidity as to the '531 patent: filed July 14, 2006 (Doc. 275 in 1:04-cv-00901-JJF), directed at asserted claims 1–4; briefed with Affymetrix's opposition (Docs. 283, 317). Motion papers: https://www.findforms.com/single_form.php/form/63700/Motion_for_Summary_Judgment_District_Court_of_Delaware_District_Court_of_Delaware_Delaware

   • Caution: one retrieved copy of this document includes proposed order language adjudging claims 1–4 invalid with the date line left blank ("this ____ day of ____, 2006"). That is consistent with a proposed form of order attached to the motion rather than an entered order. I could not verify from the sources retrieved whether the motion was granted, denied, or never decided. Do not treat the '531 claims as adjudicated invalid on this record.

3. Jury verdict (phase 1): March 5–13, 2007 — the Delaware jury found Illumina infringed (and induced infringement of) all five asserted patents, including the '531 patent, set a 15% royalty, and awarded ~$16.7 million in damages for sales through 2005. Validity, enforceability, inequitable conduct and Illumina's antitrust/unfair-competition counterclaims were expressly deferred to later phases (which never occurred, due to the settlement). Illumina press statement: https://www.siliconinvestor.com/readreplies.aspx?msgid=23365124

   • Note: the infringement verdict did not include a validity finding on the '531 patent.

4. Settlement: January 10, 2008 — Illumina paid Affymetrix a one-time $90 million; Affymetrix dismissed with prejudice all lawsuits it had brought against Illumina; Illumina dismissed its counterclaims; mutual covenants not to sue (with a carve-out for photolithography). This resolved the Delaware case plus parallel actions in Düsseldorf, Germany and the High Court of Justice (Chancery Division, Patents Court), London: https://www.fiercebiotech.com/biotech/affymetrix-and-illumina-settle-their-patent-disputes

Related proceeding (not litigation, but directed at this patent)

• Ex parte reexamination of the '531 patent, USPTO serial no. 90/008,888, requested by Illumina on October 19, 2007; reexamination ordered/announced December 21, 2007 (along with 90/008,885 for 6,355,432; 90/008,886 for 5,795,716; 90/008,889 for 6,646,243). Source: https://patentdocs.org/2008/01/02/uspto-to-reexam-2/ and https://www.genomeweb.com/archive/uspto-re-examine-two-more-patents-affymetrix-illumina-litigation
  • I could not confirm the final reexamination outcome for 90/008,888 (e.g., whether a reexamination certificate issued confirming or cancelling claims 1–4). Treat as unknown in this report. The patent shows as "Expired – Lifetime" (anticipated expiration June 7, 2015) on Google Patents.

Matters I checked but could NOT tie to the '531 patent

• Affymetrix's second-wave suits (October 2007) — U.S. (Delaware), U.K. and Germany — asserted five additional U.S. patents not addressed in the Delaware case, so the '531 patent does not appear to have been asserted in those. Reported at: http://www.foleyhoag.com/~/media/Files/Publications/Generic/1107%20DeAnne%20Smith%20Affymetrix%20Illumina%20Reprint.ashx
• Illumina, Inc. v. Affymetrix, Inc., W.D. Wis. No. 09-cv-277-bbc (2009–2010). This is a real Affymetrix/Illumina dispute reflected in Illumina's filings, but I retrieved no source identifying 5,545,531 as a patent-in-suit there. I cannot confirm or deny '531's involvement — flagging as unverified rather than asserting.
• Google Patents' "Family has litigation" data for US5545531 (family ID 23893507) points to only one case record — the Delaware 1:04-cv-00901 action — consistent with the single-litigation picture above: https://patents.google.com/patent/US5545531/en
• No ITC (Section 337) investigation, no Federal Circuit appeal, and no other district-court case asserting 5,545,531 were found in the sources retrieved. Because the Delaware case settled at the phase-1 stage and was dismissed with prejudice, there is no appellate decision construing or invalidating the '531 claims.

Bottom line

One known litigation asserted US 5,545,531: Affymetrix, Inc. v. Illumina, Inc., D. Del. No. 1:04-cv-00901-JJF, filed July 26, 2004, in which the '531 patent was one of five (originally six) patents-in-suit. The jury found infringement of the '531 patent in March 2007; Illumina's invalidity challenge to '531 (summary-judgment motion filed July 14, 2006, and an ex parte reexamination 90/008,888 ordered December 2007) was never finally adjudicated because the parties settled on January 10, 2008 ($90 million payment; all suits dismissed with prejudice). If you need the docket-level confirmation of the disposition of Illumina's '531 summary-judgment motion and the reexamination certificate for 90/008,888, those would require pulling the PACER docket for 1:04-cv-00901-JJF and the USPTO reexamination file — I could not verify either from the sources retrieved.

I'll verify the PTAB picture with live searches before writing anything, since the structured block says "no AIA proceedings on file."

Reexaminations, not AIA trials, appear in the initial results. Let me dig specifically for IPR/PGR/CBM activity and the litigation/reexam outcomes.

Proceedings overview

Zero (0) AIA trial proceedings are on file against US 5,545,531 — the USPTO Open Data Portal returns no IPR, PGR, or CBM for this patent, and my independent web/PTAB searches surfaced none. Breakdown: 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denials. There is therefore no IPR-sourced claim-level outcome to brief a defendant on, and no § 315(e)(2) estoppel in the chain. What exists instead is (i) a 2004–2007s-era district court assertion and (ii) ex parte reexaminations — neither of which is an AIA trial. One important trap: search engines return heavy PTAB traffic for US 9,399,531 (a sheet interleaver, Weber v. Provisur) — a different patent that merely shares the trailing digits 531. None of that activity is about US 5,545,531.

No AIA trial proceeding — this is the complete § 6 answer

• Type: N/A (no IPR / PGR / CBM petition was ever filed)
• Filed: N/A
• Status: No PTAB activity on file (per the structured USPTO ODP block supplied in the prompt; confirmed by web search)
• Judge panel: N/A
• Petition grounds: N/A — no petition exists, so there is no claims/art/§ 102/§ 103/§ 112 record to report
• Institution decision: N/A
• Final Written Decision: N/A — no claim of the '531 patent has ever been canceled, confirmed, or otherwise adjudicated by the PTAB
• Settlement / termination: N/A
• Appeal: N/A (no PTAB FWD to appeal)
• Defensive value: A defendant cannot rely on any PTAB outcome, but—equally—faces no adverse PTAB precedent. Any IPR-based defense must be built from scratch. Two statutory gates matter before you file: (1) § 315(b) — a petition is time-barred one year after service of a complaint alleging infringement of the patent; (2) PGR is unavailable (the '531 patent's effective filing date is 1995-06-07, long before AIA § 3's 2013-03-16 PGR cutoff), and CBM is unavailable in substance (this is a microarray/fluid-handling apparatus, not a "financial product or service"), independent of CBM's 2020-09-16 sunset for new petitions.

Adjacent matters that are not AIA trials (do not mislabel these as IPRs)

(A) Ex parte reexamination — requester: Illumina, Inc. (control no. reported as 90/008,888)

• Type: Ex parte reexamination (35 U.S.C. §§ 301–307); not an AIA trial, no PTAB involvement
• Filed: reexamination requests filed 2007-10-19; reexamination ordered/announced 2007-12-21
• Status: ordered by the USPTO on a substantial-new-question-of-patentability finding; final outcome not verified — I could not retrieve the reexamination certificate, so I will not state that any claim was canceled or confirmed
• Scope: Illumina requested reexamination of all claims of the '531 patent
• Defensive value: Useful prior-art-on-the-record ammunition only. Ex parte reexamination by a third-party requester creates no § 315(e)(2) estoppel (that estoppel is IPR/PGR-specific) and no PTAB claim-construction precedent for your case.
• Sources: https://patentdocs.org/2008/01/02/uspto-to-reexam-2/ ; https://www.genomeweb.com/archive/uspto-re-examine-two-more-patents-affymetrix-illumina-litigation

(B) Affymetrix, Inc. v. Illumina, Inc., D. Del. No. 1:04-cv-00901-JJF (the litigation flagged in the "Family has litigation" data)

• Filed: 2004-07-26 (complaint); the '531 patent was one of the asserted patents, alongside US 6,355,432; 6,646,243; 6,399,365; and 5,795,716
• Markman: order issued 2006-08-16 by Judge Joseph J. Farnan — Affymetrix, Inc. v. Illumina, Inc., 446 F. Supp. 2d 277 (D. Del. 2006), construing "probe array" and other terms, including the claim 1 language of the '531 patent ("A method for making a biological chip plate comprising the steps of: (a) providing a body comprising a plurality of wells defining spaces; (b) providing a wafer comprising on its surface a plurality of probe arrays, each probe array comprising a collection of probes, at least two of which are different, arranged in a spacially defined and physically addressable manner; (c) attaching the wafer to the body so that the probe arrays are exposed to the spaces of the wells.") — https://www.courtlistener.com/opinion/[2315392](/patent/2315392)/affymetrix-inc-v-illumina-inc/
• Invalidity challenge at the district court: Illumina filed a motion for summary judgment of invalidity of the asserted claims of the '531 patent on 2006-07-14 (D.I. 275). The motion papers contain a proposed order reading "the asserted claims 1-4 of U.S. Patent No. 5,545,531 are hereby adjudged to be invalid." ⚠️ This is a proposed order attached to a motion, not a court ruling. I could not verify from the sources retrieved whether the court granted that motion, and contemporaneous reporting of a March 2007 jury verdict finding Illumina liable on Affymetrix's asserted patents indicates the '531 claims may have reached trial. Treat claims 1–4 as TESTED but with an unverified district-court outcome — not as canceled. Source for D.I. 275: https://www.findforms.com/single_form.php/form/63700/Motion_for_Summary_Judgment_District_Court_of_Delaware_District_Court_of_Delaware_Delaware
• Defensive value: The 446 F. Supp. 2d 277 construction of "probe array" and the surrounding prosecution/claim-construction record remain the best free ammunition for a non-infringement or § 112 position today; the 2007-era reexamination art gives you a ready-made § 102/§ 103 starting set for a fresh IPR.

Strategic summary

Claim status. Because the PTAB never touched this patent, no claim of US 5,545,531 is CANCELED by the PTAB, and no claim is SUSTAINED by the PTAB. All four claims (1–4; claims 1 and 3 independent, claims 2 and 4 depending from them and limited to DNA/RNA probes) are UNTESTED at the PTAB. The only validity/adjudication events I can document are (a) Illumina's 2006-07-14 summary-judgment motion whose proposed order would have invalidated claims 1–4, and (b) an ordered ex parte reexamination in which every claim was placed at issue — with no certificate retrieved. Do not tell a court or client that claims 1–4 are canceled; that would be unsupported. Note that the '531 reexamination-era and litigation-era art is largely pre-AIA § 102/§ 103 art, so your IPR must plead pre-AIA §§ 102(a)/(b)/(e) and 103(a) as applicable to a 1995 filing.

Estoppel landscape. There is no § 315(e)(2) estoppel — the statute conditions it on a petitioner obtaining an IPR Final Written Decision, and there has never been an IPR. Likewise no § 325(e)(2) PGR estoppel. Illumina's ex parte reexamination request does not estop anyone (neither Illumina nor its privies) from raising the same art in your district court case or in a new IPR; the ex parte statute simply lacks an IPR-style estoppel provision. Practically, the entire universe of prior art — including all the art Illumina put into 90/008,888, and any art it did not — is available to you as of today.

Pattern signals. No petitioner has ever filed an IPR on this patent; there is no recurring PTAB petitioner, no defensive aggregator (Unified Patents or similar) in the chain, and consequently no PTAB appeals to the Federal Circuit. The patent's Google Patents legal-status line is "Expired – Lifetime" with an anticipated expiration of 2015-06-07, and the file lists no PTAB litigation-history events, only the Delaware case and Darts-ip family litigation. The 2004–2007 campaign against Illumina was patent-owner-side enforcement, with the target responding by reexamination rather than by AIA trial (which did not yet exist). The only later activity in the family is a chain of continuations/divisionals all claiming the same 1995-06-07 priority (US 5,874,219; US 2002/0018991; US 6,720,149; and the 2004–2005 publications) — which is a "same-family, same-priority" signal, not a fresh adversarial proceeding.

Recommended next steps

1. Start from "no PTAB activity on file," stated affirmatively. The absence is itself a signal, and here it is a strong one: this patent was aggressively asserted in 2004 and yet never drew an IPR. That reflects the pre-AIA timing of the fight and the 2015-06-07 expiration, not any weakness of the patent on the merits.
2. Check the expiration math before funding any defense. The '531 patent expired 2015-06-07 (20 years from the 1995-06-07 filing) per its own legal-status record, and its direct continuations (US 5,874,219; US 6,720,149) share that priority and 20-year clock. If a demand letter is asserting the '531 patent for ongoing post-2015 conduct, that theory is defective on its face; recovery would be limited to back damages within the § 286 six-year lookback. Verify with the USPTO's PatentCenter file wrapper before relying on this.
3. Retrieve the reexamination certificate for control no. 90/008,888 (also reported as a related Illumina request per the same 2007-10-19 filing date) via Patent Public Search / PatentCenter under the "Reexamination Certificate" tab. That single document will tell you whether any of claims 1–4 were canceled or confirmed and whether claim scope was amended — and it is the closest thing to a "claim-level outcome" this patent has. The USPTO's PTAB E2E (https://ptacts.uspto.gov/ptabweb/) will confirm the nil PTAB result.
4. Resolve the 2006-07-14 D.I. 275 summary-judgment motion. Pull the D. Del. docket for 1:04-cv-00901-JJF (https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A04-cv-00901) and the post-trial/Final Judgment documents to determine whether claims 1–4 were ever adjudged invalid and how the case terminated. If a judgment of invalidity of claims 1–4 was entered and affirmed/unappealed, that is a collateral-estoppel-grade weapon (not a PTAB one); if not, the 446 F. Supp. 2d 277 constructions are your non-infringement path.
5. If you are being asserted against and want an IPR, move within one year of service of the complaint (§ 315(b)) and build the petition on the pre-AIA art set Illumina surfaced in the reexamination plus any art not previously presented to the Office (mind § 325(d)). Because there is no prior IPR, you will face no § 315(e)(2) estoppel from anyone, and there is no FWD to quote — because none exists.
6. Do not cite the 9,399,531 PTAB papers (Weber, Inc. v. Provisur Technologies, petitions at https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1528326](/patent/1528326)/download-documents) in any filing about US 5,545,531; they concern a food-slicing sheet interleaver and would be a sanctionable mix-up.

Confidence statement. High confidence: zero AIA trial proceedings on US 5,545,531; the existence and dates of the Illumina-filed ex parte reexaminations (requests 2007-10-19; ordered 2007-12-21); the D. Del. case number and filing date; the 2006-08-16 Markman ruling at 446 F. Supp. 2d 277; the 2015-06-07 expiration line. Lower confidence / explicitly unverified: the disposition of Illumina's 2006-07-14 summary-judgment motion, whether claims 1–4 were ever held invalid in the district court, and the claim-level outcome of reexamination 90/008,888. I have flagged, rather than filled, those gaps.