US 10126236

I'll search for this specific patent number across both patent databases and court dockets.

Let me run additional targeted searches to verify litigation status and confirm the bibliographic data.

Let me do one final check for any litigation or PTAB proceedings involving this patent or its family.

Summary — US Patent No. 10,126,236 (interpreted literally as requested)

Verification note on scope: I searched for the exact identifier "10126236" / "10,126,236." No CAFC 2026 docket and no PTAB proceeding matching this patent number appeared in any search result. All CAFC 2026 results returned were unrelated cases (e.g., Fortress Iron v. Digger Specialties, Spero v. Mercedes-Benz, AudienceScience v. Google). I cannot certify the absence of litigation with high confidence, since docket searches via general web search are not exhaustive — but nothing surfaced tying this patent to any court or Board proceeding.

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Bibliographic data

Inventors (as listed): Manfred Battefeld; Michael Kussmann; Bas de Heij; Bernd Gassner; Frank Steinhauer; Hans-Joachim Kumpch; Axel Leyer; Michael Kueppers; Andreas Golitz; Andreas Mitreiter; Clemens Hanschke; Lothar Heidemanns.

⚠️ Ownership anomaly (flagging, not auto-correcting)

The Google Patents legal-events record for this patent shows a 2018-01-02 reassignment to "MICROSOFT TECHNOLOGY LICENSING, LLC" with the assignor named as "TIPPANA, SREEVANI" (Reel/Frame 044518/0088), and lists Microsoft as a "current assignee." This is facially inconsistent with the patent's subject matter, inventors, and original assignee. The record simultaneously shows a maintenance-fee payment on 2026-05-06 identifying the patent owner as a LARGE ENTITY but does not name the owner. I am treating the Hach Lange GmbH ownership as authoritative (matching the WO/EP family, all naming Hach Lange GmbH) and the Microsoft entry as a likely database artifact, but I cannot resolve this definitively from the available sources. Recommend confirming current ownership via USPTO PatentCenter / the USPTO Assignment database before relying on it.

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Abstract (as granted)

A method for detecting contamination of a cuvette of a turbidimeter. The turbidimeter includes a light source emitting a light beam toward a cuvette, a scattering light detector, and a diffuser with a body and an actuator. The actuator moves the body between a parking position and a test position where the body sits between the light source and the cuvette, interferes with the beam, and generates diffuse test light entering the cuvette. The method includes activating the actuator to move the body into the test position, activating the light source, measuring a test light intensity at the scattering detector, comparing that intensity with a reference light intensity, and generating a contamination signal if the difference exceeds a first threshold.

Plain-language overview of the claims

Claim 1 (independent) — the core method. The environment is a nephelometric turbidimeter having (a) a measurement light source emitting an axial parallel beam toward a cylindrical sample cuvette with a cylinder wall; (b) a scattering light detector; (c) a diffuser with a body and an actuator that moves the body between a parking position (out of the beam) and a test position (between source and cuvette, generating diffuse test light); and (d) a cleaning device that mechanically cleans the inner side of the cylinder wall. The method steps are: move the diffuser into the test position; turn on the light source; measure the test light intensity at the scattering detector; compare it to a reference intensity; generate a contamination signal if the difference exceeds a first threshold; activate the cleaning device if a contamination signal was generated; and re-request the contamination test after cleaning finishes. The two closing steps (auto-clean then re-test to verify) are what distinguish claim 1 from the parent patent's claims.

Claim 2 (dependent on 1). Adds a light source detector assigned to the diffuser body that directly receives the diffuse test light when the body is in the test position. In that state, the method additionally measures the light source intensity at that detector and compares it with a reference light source intensity.

Claim 3 (dependent on 2). Adds closed-loop control: the measurement light source's intensity is controlled via the light source detector so that the measured light source intensity equals the reference light source intensity (i.e., normalizing source output to a reference level).

Claim 4 (dependent on 3). Adds a lamp-health function: comparing the electrical energy used to generate the reference light source intensity against an electric-energy reference, and generating a lifetime signal if the difference exceeds a second threshold (an end-of-lamp-life indication).

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Technical context (from the specification)

• The diffuser body may be a transparent matrix (e.g., PMMA) filled with scattering particles (calcium phosphate, fluorides, stannic oxide, titanium oxide; particle size ~1.0–5.0 µm), or frosted glass.
• The scattering detector is off-axis (typically ~90°); the light source may be a laser LED.
• Background art discussed: US 2011/0043807 A1 (Endress+Hauser), criticized as requiring two sources/two detectors and being confounded by turbidity inhomogeneities.
• Figure roles: Fig. 1 = measurement mode (diffuser parked); Fig. 2 = test mode, clean cuvette; Fig. 3 = test mode, contaminated cuvette (fouling layer 70).

Uncertainty statement

I have high confidence in the bibliographic fields, claim text, and abstract, all drawn from the authoritative full text supplied. I have lower confidence on (i) current ownership status given the contradictory Microsoft assignment record noted above, and (ii) the completeness of the CAFC/PTAB litigation check, since no authoritative docket database returned a match and I was unable to run the final confirming queries.

I'll search for litigation involving US patent 10126236 across patent litigation sources.

Initial searches returned irrelevant results. Let me search the specialized litigation portals and dockets directly.

Let me search additional litigation-specific databases and docket sources.

Findings: Litigation Search for U.S. Patent No. 10,126,236

Bottom line: I found no litigation — no district court action, no ITC investigation, no PTAB proceeding, and no CAFC appeal — involving U.S. Patent No. 10,126,236.

What I did

I ran targeted searches keyed to the exact number (both "10126236" and "10,126,236") and to the patent's subject matter and owner, with the intent of reaching patent‑litigation sources (Unified Patents Litigation Caselist, CourtListener/RECAP, Justia Dockets, Docket Alarm, CAFC):

• US patent 10126236 litigation
• "10126236" patent lawsuit defendant
• portal.unifiedpatents.com litigation "10126236"
• courtlistener "10126236" patent case Hach Lange
• Hach Lange GmbH patent infringement lawsuit turbidimeter
• "nephelometric turbidimeter" patent litigation Hach Lange infringement sued
• "10126236" OR "10,126,236" patent infringement complaint district court

What those searches returned

Every hit for the bare string "10126236" was a false positive — a different identifier that happens to share the digits:

• DE 10126236 A1 / EP 1286454 — a Harman/Becker Automotive Systems switching‑regulator application (unrelated German priority document).
• UK company number 10126236 — "Horleys (Yorkshire) Ltd" (Companies House filing), not a patent case.
• Brazilian and civil‑service records referencing unrelated serial numbers (e.g., a Toledo scale serial number).

The only results that actually pertained to U.S. 10,126,236 were patent‑document copies of the patent itself (e.g., the Google Patents PDF US10126236.pdf), its WO/PCT parent WO 2015/043675 A1, and family/assignee pages — i.e., prosecution and bibliographic data, not litigation. I found the same for the closely related Hach Lange turbidimeter patent US 9,410,882, which likewise surfaced only as patent documents, not as a litigated patent.

Why this is unsurprising

U.S. 10,126,236 is a divisional of U.S. 9,851,297 (from PCT/EP2013/070353), owned by Hach Lange GmbH (a Danaher‑family water‑analysis company). It is a narrow, apparatus‑specific patent directed to a diffuser‑based cuvette‑contamination test in a nephelometric turbidimeter. There is no indication it has been asserted.

Important caveats

1. Scope of my search. I was working from public web results; I could not execute live, parameterized queries against the Unified Patents Litigation Caselist, PACER, or Westlaw/Lexis. A negative result here is strong but not a guarantee, especially for very recent filings (search snapshots can lag) or for cases where the patent is asserted but its number is not indexed in free text.
2. Verify independently. To confirm, run the exact number on:
   • Unified Patents portal: https://portal.unifiedpatents.com/litigation/caselist?patents=10126236
   • Unified Patents PTAB caselist: https://portal.unifiedpatents.com/ptab/caselist?patents=10126236
   • CourtListener/RECAP and PACER (search "10,126,236").
3. Bibliographic anomaly, taken literally per your rule. The Google Patents record for this patent shows an assignment to MICROSOFT TECHNOLOGY LICENSING, LLC (recorded 2018‑01‑02, assigning from "TIPPANA, SREEVANI"), while the original assignee and applicant is Hach Lange GmbH. This is almost certainly a data‑entry error in the source, but I am reporting it exactly as shown rather than "correcting" it. It has no bearing on the litigation question — no case was found under either name.

Conclusion

On the record available to me, there is no known litigation involving U.S. Patent No. 10,126,236. If you need a litigation‑grade clearance opinion, I recommend confirming this against a paid docket service (Docket Navigator, Lex Machina, or PACER/RECAP direct) before relying on it, since those sources carry full coverage and real‑time updates that open web searching does not.

PTAB / AIA Trial Proceedings — US Patent No. 10,126,236 ("Method for detection of the contamination of a sample cuvette of a nephelometric turbidimeter")

Sourcing note: The canonical structured block ("PTAB proceedings on file," from the USPTO Open Data Portal) lists zero AIA trial proceedings for this patent. I independently attempted to corroborate that via web search (petitioner-side and patent-owner-side queries, plus generic "10126236 IPR/PGR" queries). Every hit referencing a "'236 patent" or a "236 IPR" in my search results involves a different patent — e.g., the Samsung v. Netlist IPR over Netlist's '236 patent, the NuVasive/Medtronic '236 patent (U.S. 7,470,236), and the FMC/Climax '236 patent in the ITC investigation. None of those is U.S. 10,126,236, and I will not import their outcomes into this analysis. I found no Federal Circuit appeal, no PTAB trial, and no defensive-aggregator filing tied to this patent number. I cannot certify a universal negative from general web search, but the ODP list and my searches agree.

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Proceedings overview

There are no AIA trial proceedings on file for US 10,126,236 — zero IPRs, zero PGRs, zero CBMs (0 active / 0 invalidated / 0 sustained / 0 settled / 0 institution-denied). Defensive posture: this patent has not been tested at the PTAB, so there is no claims-canceled safe harbor to lean on — but equally, no petitioner has yet found art good enough to take a shot at it, and the patent family's prosecution history shows the claims (including the auto-clean-then-re-verify steps added at divisional stage) were vetted by multiple foreign examiners. A defendant should treat the claims as intact and entirely un-adjudicated.

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No proceedings to report

There is no {PROCEEDING_NUMBER} entry to populate. For completeness, the following is what a "no activity" finding rests on:

• USPTO ODP AIA trial feed — no IPR/PGR/CBM petition naming US 10,126,236 (application 15/806,343) or its parent US 9,851,297 (application 15/025,553).
• Web corroboration searches — no PTAB docket entry, FWD, institution decision, or settlement termination order surfaced for this patent.
• Federal Circuit — no appeal docket tied to this patent surfaced (this is expected: there is no FWD to appeal).
• Defensive aggregators — no Unified Patents / RPX-style challenge identified.

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Strategic summary

Claim status — all four claims are live and un-adjudicated. Because no AIA trial has been instituted, there is no claim-level outcome table to build. Claims 1–4 of US 10,126,236 stand as issued on 2018-11-13, all still enforceable, none canceled, none narrowed by a Board decision. Contrast this with the parent, US 9,851,297 — also, per the same record, free of PTAB activity. The practical consequence is that a defendant cannot point to any PTAB disposition and say "the claims you're asserting are already dead."

Estoppel landscape — nothing on the table, which cuts both ways. Section 315(e)(2) estoppel is only triggered by a petitioner who reaches a final written decision. With no petitioner and no FWD, there is no estoppel operating against anyone on this patent. That is a two-sided fact: a defendant has a completely clean slate to raise § 102/§ 103 art at the PTAB or in district court, but it also means no prior petitioner has bled out the cost/risk of an early validity test or narrowed the claim construction battlefield for you. Any art you want to run, you run first, at full cost, with no roadmap from a prior panel.

Pattern signals — none. No serial petitioner (no one has filed even once), no aggressive patent-owner PTAB appellate posture (there are no adverse decisions to appeal), no defensive aggregator in the chain. The patent is commercially and technically narrow — a fairly specific contamination-test methodology for a nephelometric process turbidimeter — which plausibly explains why it has not attracted IPR attention: the pool of real-world infringers is small, and the art is specialized.

Cross-reference flag (carried forward, unresolved): the Google Patents legal-events record for this patent still shows a facially erroneous 2018-01-02 assignment to Microsoft Technology Licensing, LLC (assignor "Tippana, Sreevani"), which is inconsistent with the Hach Lange GmbH family. This does not affect the PTAB analysis (no proceeding turns on ownership), but it does affect who a defendant would be negotiating a license with. Confirm current ownership via USPTO PatentCenter / the Assignment database before relying on the ownership chain.

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Recommended next steps

If no PTAB activity exists (this is the case here), say so plainly — and treat the absence as a signal. Well-asserted patents eventually attract IPRs; this one has not, which suggests either (a) it is not being aggressively asserted, or (b) accused products are few and the art is difficult. Do your own pre-suit art search rather than waiting for a Board decision that will never come.

For a defendant contemplating an IPR challenge:

• The statutory clock is entirely yours to start. If you file, the Board's institution decision is due within 6 months of the petition's filing date (35 U.S.C. § 314(b)), and any final written decision is due within 12 months of institution (§ 316(a)(11)).
• Art to prioritize: focus on the divisional-added limitations that distinguish claim 1 from the parent — specifically the cleaning-device activation on a contamination signal and the automatic re-request/re-verification of the contamination test after cleaning. Those interactive steps are claim 1's narrowest points and the most likely locus of a § 103 combination. Independent claim 1 requires them; claims 2–4 layer on (2) a diffuser-assigned light source detector, (3) closed-loop source-intensity normalization, and (4) a lamp-lifetime signal based on electrical-energy-to-reference comparison. If you cannot reach those added steps, the parent patent's broader claims may be the more vulnerable target — consider them together.
• Check the prosecution-history references cited against the family (e.g., US 2011/0043807 A1 to Endress+Hauser, discussed as background art, and the Hach lineage of US 5,506,679, 5,912,737, 6,307,630) as a starting art set.

Pointers for verification (use these rather than relying on this memo alone):

• PTAB proceedings search: USPTO Patent Trial and Appeal Board End-to-End (PTAB E2E) — https://ptacts.uspto.gov/ (search by patent number 10126236)
• USPTO Open Data Portal AIA trials API — the source of the canonical "no proceedings" finding
• USPTO PatentCenter for application 15/806,343 and 15/025,553 — https://patentcenter.uspto.gov/
• USPTO Patent Assignment Search (to resolve the ownership anomaly) — https://assignment.uspto.gov/
• CourtListener / CAFC docket for any future appeal — https://www.courtlistener.com/ and https://cafc.uscourts.gov/

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Bottom line for a defendant: No PTAB activity exists on US 10,126,236. There is no FWD to cite, no canceled claims to point at, and no § 315(e)(2) estoppel to exploit. You are facing a clean, un-adjudicated four-claim patent whose divisional-added limitations (auto-clean + re-verify) are the narrowest and most attackable part of claim 1. Any validity challenge is yours to make, first, from scratch.

I'll research the assignment record for this patent. Let me run targeted searches.

Let me search the USPTO Assignment Center directly and investigate the anomalous Microsoft record.

Assignment / Ownership Analysis — US 10,126,236 B2

Scope note / limitation first. I attempted to query the USPTO Assignment Center (https://assignmentcenter.uspto.gov/) and the legacy Assignment Search (https://assignment.uspto.gov/patent/index.html) directly. My available tooling is general web search, which does not render those database UIs, so I could not pull the raw reel/frame records the way a PatentCenter session would. What follows is built from (a) the authoritative granted-patent text supplied, (b) the Google Patents legal-events record embedded in that text, and (c) cross-checks against the family and the assignee's corporate disclosures. Anything below marked [unverified] should be confirmed in PatentCenter before reliance. I have not fabricated any reel/frame numbers.

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Inventors

All twelve named inventors appear to be employees of the original assignee, Hach Lange GmbH (German water-analysis instrumentation), consistent with the family record listing the same team across the WO/EP/US siblings (e.g., CN105637342B lists the identical twelve and names Hach Lange GmbH as applicant).

Pattern assessment: This is a large, multi-site corporate R&D team (Düsseldorf and Berlin facilities), which is the opposite of the single-inventor, lone-consultant profile typical of NPE-origin patents. There is no evidence of inventors departing the assignee or of an inventor-name reassignment (which is a classic precursor to a fire-sale). I found nothing indicating any inventor separately assigned rights. The locations above are drawn from sibling-family bibliographic listings and should be treated as indicative, not certified.

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Original assignee

Hach Lange GmbH (Germany). Two addresses appear across the family records: Willstätterstraße 11, D-40549 Düsseldorf and Königsweg 10, 14163 Berlin. Both are Hach Lange GmbH sites.

• Primary business: design and manufacture of laboratory and process water-analysis instruments — turbidimeters, spectrophotometers, colorimeters, sampling and analysis systems. This is squarely an operating company.
• Product embodiment: Hach ships commercial turbidimeters (lab and process lines). The claimed subject matter (cuvette-fouling detection via a switchable diffuser in a nephelometric turbidimeter) is consistent with a diagnostic feature of a process/lab turbidimeter rather than a paper-only asset. I did not locate a marketing document tying the specific claim steps to a named SKU number, so treat "ships an embodying product" as high-probability but [unverified to SKU level].
• Corporate status: Hach Lange GmbH is part of the Hach group (Hach Company, Loveland, CO), historically under Danaher Corporation and, since the July 2016 Fortive spin-off, within the Fortive industrial portfolio. Operating — not dissolved, not in bankruptcy. No Chapter 7/11 event is implicated.

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Assignment timeline

Key finding: the Assignment Center record for this patent contains no genuine post-issuance chain. The only assignment-type legal event visible for US 10,126,236 is an entry that is facially inconsistent with this patent and appears to be a database mis-link rather than a real transfer of this asset.

• 2018-01-02 (recorded) — Reel 044518/0088
  • Conveyance: Assignment
  • Assignor as recorded: TIPPANA, SREEVANI
  • Assignee as recorded: MICROSOFT TECHNOLOGY LICENSING, LLC (Washington)
  • Correspondent: not exposed in the surfaced record [unverified]
  • Context: Database artifact / mis-link — not a transfer of this patent. None of the twelve Hach inventors is named "Tippana," there is no Hach-to-Microsoft relationship in this family, and a single individual assignor ("Sreevani Tippana") assigning to Microsoft is the signature of an employee invention-assignment for an unrelated Microsoft patent whose reel/frame (044518/0088) has been cross-attached to this record. It is not a shell-entity or NPE event.
  • Correspondent recurrence: cannot be assessed — no correspondent was surfaced.

No other recorded assignments. In particular, there is no Hach Lange → (IP Holdings / Licensing / Ventures LLC) transfer, no security-interest/security-agreement lien against the patent, no merger or change-of-name recording, and no transfer to any entity on the standard NPE rosters. The Google Patents legal-events feed shows only (i) the original application filing by Hach Lange GmbH (2017-11-08), (ii) grant (2018-11-13), and (iii) maintenance-fee payments on 2022-04-27 (4th year) and 2026-05-06 (8th year), both recorded as LARGE ENTITY — consistent with a large operating corporate owner (the Hach/Fortive group) continuing to pay to keep the patent alive.

Because no genuine assignment beyond the original is present, the chain effectively terminates at the original assignee.

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Timeline diagram

timeline
    title Ownership of US 10126236
    2013 : PCT filed by Hach Lange GmbH
         : Priority date for the family
    2016 : US national phase entry
    2017 : Divisional application filed
    2018 : Patent granted to Hach Lange
         : Microsoft record is a database artifact
    2022 : Fourth year maintenance fee paid
    2026 : Eighth year maintenance fee paid

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NPE / troll-pattern signals

Caveat on the ownership anomaly (carried forward from the prior section — no contradiction). The "[MICROSOFT TECHNOLOGY LICENSING, LLC] current assignee" line on Google Patents, sourced from Reel 044518/0088 / assignor "TIPPANA, SREEVANI," is the same anomaly already flagged in the previously generated summary. It is a bibliographic artifact, not evidence of an NPE chain, and it should not be read as a Microsoft ownership interest in this turbidimeter patent. Recommend confirming the true owner and the absence of any genuine encumbrance in USPTO PatentCenter / the Assignment Search UI.

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Verdict

Insufficient data — specifically: no genuine assignment record beyond the original, which leaves the patent with its operating-company originator.

This is a "clean chain" outcome rather than an NPE outcome. The only recorded post-filing legal event for US 10,126,236 is the 2018-01-02 Reel 044518/0088 entry naming assignor "TIPPANA, SREEVANI" and assignee "MICROSOFT TECHNOLOGY LICENSING, LLC," which is facially inapplicable to this patent and best explained as a Google Patents cross-link error. With that artifact excluded, ownership runs and rests at Hach Lange GmbH, an operating water-analysis instrumentation manufacturer (Hach/Fortive group), which has continued paying large-entity maintenance fees (4th year 2022-04-27; 8th year 2026-05-06). There is no shell transfer, no known asserter, no cascading chain, no bankruptcy sale, and no defensive-aggregator termination — i.e., zero concrete NPE signals.

Verify at: https://assignmentcenter.uspto.gov/ (search "10126236" / application 15/806,343) and the companion PEDS/ODP record — request the full reel/frame detail, including the correspondent of record, to (i) confirm no genuine Hach→third-party conveyance exists and (ii) definitively rule the Microsoft entry in or out as an artifact.

Confidence: High that no NPE chain is present in the surfaced record; moderate on absolute completeness, because I could not open the Assignment Center UI directly and am relying on indexed legal-event data plus family cross-checks.

I'll verify the patent at USPTO and examine its cited references.

Let me gather details on the cleaning-related and remaining cited references.

Prior-Art Analysis — U.S. Patent No. 10,126,236 B2

0. Scope, sources, and a constraint on this round

• The patent is confirmed at https://patents.google.com/patent/[US10126236](/patent/US10126236)/en ("Method for detection of the contamination of a sample cuvette of a nephelometric turbidimeter," Hach Lange GmbH, granted 2018‑11‑13, app. 15/806,343).
• The prior-art list below is taken from the citation tables printed on/associated with the patent record (Google Patents "Citations (26)" and the expanded "Patent Citations (28)"). The two lists differ by exactly two entries — the U.S. family members of the Bosch reference — so the union is 28 patent citations + 2 non-patent citations.
• Tooling caveat: I hit the tool-call limit while pulling full text for four of the less-central references (US 5,506,679; US 5,912,737; US 9,329,195; US 8,873,052). For those I rely on the authoritative citation table (number, dates, assignee, title) plus general knowledge, and I mark them as not independently re-verified in this session. I did not gather full text on any reference I present as "detailed."

1. The governing legal frame (dates matter here more than usual)

• Effective filing date / priority: 2013‑09‑30 (PCT/EP2013/070353). Because this is after March 16, 2013, the AIA version of 35 U.S.C. § 102 (first‑inventor‑to‑file) governs — not pre‑AIA § 102.
• AIA § 102(a)(1) art = patents, printed publications, public uses, sales, or "otherwise available to the public" before 2013‑09‑30.
• AIA § 102(a)(2) art = U.S. patents/applications effectively filed before 2013‑09‑30 (even if published later).
• Critically: a foreign document (CN/JP/EP/WO) that published after 2013‑09‑30 is not prior art, regardless of its filing date.

This last point knocks out two of the 28 citations outright, and a priority-date problem knocks out two more (below).

2. The 28 cited patent references

Legend for the last column: ANT? = could this single reference anticipate any of claims 1–4 under § 102? ("No" is used where at least one claim‑1 element is missing — anticipation requires every element in one reference.)

Non-patent citations (2): both are the CN Office Action dated 2018‑01‑10 and its English translation. These are prosecution documents, not prior art.

Anomaly (reported literally, not corrected): the "Families Citing this family" list also shows three entries with no apparent technical relation — JP 3085348 B2 (Mitsubishi Motors, "Transfer device for four‑wheel drive vehicles"), JP 4749913 B2 and JP 4754459 B2 (Honda, "Vehicle drive switching mechanism/lever"). These are almost certainly database mis‑links, but I am reporting the identifiers exactly as the record shows them rather than "fixing" them.

3. The four references worth real discussion

3a. US 4,165,179 A — Sato / Nippon Precision Optical Instrument (the cleaning reference)

• Citation: US 4,165,179 A, filed 1976‑08‑19, granted 1979‑08‑21. https://patents.google.com/patent/US4165179
• Disclosure: a motor‑driven wiper/brush inserted into a cylindrical (or longitudinal) sample cell that mechanically wipes the inner surface of the optical window, on demand or periodically, "whenever the inner surface of the sample cell is smeared." It explicitly addresses that wall smear corrupts the turbidity reading.
• § 102 vs claims 1–4: No anticipation. It supplies the "cleaning device … mechanical cleaning of an inner side of the cylinder wall" element of claim 1, but discloses none of: the switchable diffuser body, the parking/test positions, the generation of diffuse test light entering the cuvette, the scattered‑light comparison against a reference, the contamination signal, or the automatic re‑test after cleaning. Under § 102 a single reference must show every element — this one does not. It is meaningful § 103 art for the cleaning sub‑step only.

3b. US 5,912,737 A — Hach Company (calibration verification)

• Citation: US 5,912,737 A, filed 1998‑06‑01, granted 1999‑06‑15, Hach Company — "System for verifying the calibration of a turbidimeter." (Level of detail from the citation table; full text not re‑retrieved this session.)
• § 102: No. Calibration verification is a different concept from a contamination test; no diffuser, no diffuse illumination of the cuvette, no cleaning/re‑test loop.

3c. US 2011/0043807 A1 — Endress+Hauser Conducta (the closest reference, and the one the patent itself attacks)

• Citation: US 2011/0043807 A1 (pub. 2011‑02‑24; priority 2008‑04‑11), Endress+Hauser Conducta GmbH+Co. KG, "Method and apparatus for turbidity measurement." https://www.freepatentsonline.com/y2011/0043807.html
• Disclosure: a four‑beam alternating‑light turbidimeter with two emitters and two detectors (plus a monitor/reference diode). Turbidity is derived from the ratio of the direct and indirect propagation paths; the turbidity value is checked for plausibility using at least one additional detector on an additional propagation path, and a warning is generated when the plausibility check fails. The specification of US 10,126,236 expressly distinguishes this reference (it "requires relatively high technical effort" and can be confounded by turbidity inhomogeneities).
• § 102 vs claims 1–4: No anticipation. The reference teaches away from the claimed architecture: it uses two sources + two detectors + an extra detector, whereas claim 1 requires one measurement source, one off‑axis scattering detector, and a movable diffuser that converts the beam into diffuse test light. Critically, US 2011/0043807 has no diffuser body, no parking/test positions, no diffuse test light entering the cuvette, no cleaning device, and no automatic re‑test after cleaning. It is the leading § 103 reference (motivation: plausibility/self‑diagnosis of a turbidimeter), but it cannot support a § 102 rejection of any of claims 1–4.

3d. US 9,182,344 B1 — Mitchell (fouling detection) — disqualified by date, despite being the most on‑topic

• Citation: US 9,182,344 B1, filed 2014‑11‑18, granted 2015‑11‑10, Herbert Mitchell — "Device for the detector of fouling on optical surfaces of a nephelometric turbidimeter submerged in a liquid." https://patents.justia.com/patent/[9182344](/patent/9182344)
• Disclosure: internal, automatic or scheduled detection of fouling on the optical windows of a nephelometric turbidimeter (source window and scattered‑light detector window) by comparing a reading against a previous reading; intended to work with the inventor's US 7,659,980 B1 self‑check/self‑calibration nephelometer.
• § 102: Not prior art at all. Its effective filing date (2014‑11‑18) is after the 2013‑09‑30 effective filing date of US 10,126,236 (AIA). It cannot anticipate or even be § 102(a)(2) art. It is nonetheless the closest conceptual neighbor to the patent's problem (fouling/contamination detection), which is presumably why it appears in the citation tables — but it is date‑barred. (Same logic disposes of #24 CN 202,886,281 U: foreign publication after the EFD.)

3e. US 9,329,195 B2 — Sysmex (container cleaning) — also date‑barred

• Filed 2013‑11‑01 (after 2013‑09‑30), granted 2016‑05‑03 — "Container cleaning device, discharge member for container cleaning device, and analyzer." Relevant to the cleaning element, but not prior art against this patent for the same AIA date reason.

4. Bottom line on § 102

No cited reference anticipates any of claims 1–4.

• Claim 1 requires the combination of (i) a diffuser body movable between a parking position and a test position between the source and the cuvette, (ii) diffuse test light entering the cuvette, (iii) an off‑axis scattering‑detector test‑light measurement, (iv) comparison to a reference with a first threshold and generation of a contamination signal, (v) activating a cleaning device if a contamination signal is generated, and (vi) re‑requesting the contamination test after cleaning. No single cited reference discloses the diffuser‑based diffuse‑illumination contamination test at all; the cleaning references (US 4,165,179) and the plausibility reference (US 2011/0043807) each supply at most one disjoint piece. This absence of single‑reference disclosure is precisely why the patent issued — and why the parent (US 9,851,297 B2) and this divisional coexist.
• Claims 2–4 (light‑source detector on the diffuser body; closed‑loop normalization of source intensity; lamp‑lifetime signal from electrical energy) depend on claim 1 and add further elements (especially the "light source detector assigned to the diffuser body") that appear in no cited reference in combination.

Most useful references for a § 103 (obviousness) challenge, in order:

1. US 2011/0043807 A1 (Endress+Hauser) — turbidity plausibility/self‑diagnosis (primary).
2. US 4,165,179 A (Sato) — mechanical cleaning of the cuvette's inner window surface.
3. US 5,912,737 A / US 5,506,679 A / US 6,307,630 B1 (Hach) — calibration/verification and nephelometer architecture.
4. US 2013/0057859 A1 / US 8,873,052 B2 / CN 102,762,972 A (Bosch) — quality/plausibility assessment of a scattered‑light measurement.
5. US 9,182,344 B1 (Mitchell) — fouling detection (conceptually closest, but date‑barred; may still be citable against a later‑priority improvement, not against this patent).

5. Confidence and open items

• High confidence: the citation list, dates, assignees, titles, and the claim texts — all from the authoritative full text supplied and the verified USPTO/Google Patents record.
• Medium/high confidence: the substantive descriptions of US 2011/0043807, US 4,165,179, US 9,182,344, US 7,663,751, US 7,659,980 (retrieved).
• Lower confidence / flagged: full‑text characterizations of US 5,506,679, US 5,912,737, US 9,329,195, US 8,873,052 were not re‑retrieved before the tool limit; their § 102 conclusions here rest on the authoritative citation data plus general knowledge and should be re‑verified if a formal opinion is needed.
• Cross‑reference to the earlier sections: the prior-art date analysis is consistent with the priority date (2013‑09‑30) already established. The Microsoft Technology Licensing LLC assignment anomaly flagged in the earlier summary does not affect the prior-art analysis (it concerns ownership, not art), and I am not auto‑correcting it.

I'll ground this analysis in the prior-art references of record for US 10,126,236, verifying the key ones before mapping them to the claims.

Obviousness Analysis — U.S. Patent No. 10,126,236 under 35 U.S.C. § 103

Building on the two prior sections (bibliographic summary; litigation summary). This section assumes the claim construction and claim-set description already established there — claim 1 independent; claims 2–4 dependent; effective filing/priority date 2013‑09‑30 — and does not repeat it.

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1. Framework and the critical date

Under Graham v. John Deere, 383 U.S. 1 (1966), obviousness is assessed against (i) the scope and content of the prior art, (ii) the differences between the prior art and the claims, (iii) the level of ordinary skill, and (iv) objective indicia. Under KSR Int'l v. Teleflex, 550 U.S. 398 (2007), a combination is obvious where the improvement is a "predictable use of prior art elements according to their established functions," and any articulable reason — including "design incentives," "market forces," and "obvious to try" — can supply the motivation.

Critical date consequence. The claims are entitled to the PCT/EP2013/070353 priority date of 2013‑09‑30. Several items in the patent's own "Cited By"/citation tables post‑date that (e.g., US 9,182,344 B1 filed 2014‑11‑18; US 9,329,195 B2 priority 2013‑11‑01; EP 3,023,768 / EP 3,026,421, 2014). These are not § 102 prior art to the claims and should be excluded from any § 103 attack. The references that do qualify are the ones relied on below.

Person of ordinary skill in the art (POSITA). A POSITA here would be an engineer or physicist with a bachelor's degree (or equivalent) in optics/instrumentation and 2–5 years of experience designing nephelometric/turbidimetric and other scattered‑light photometers, familiar with in‑line process analyzers, cuvette handling, lamp/detector drive electronics, and automated cleaning/calibration subsystems.

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2. Mapping claim 1 against the prior art of record

Claim 1 is a system‑plus‑method claim. Its environment is a nephelometric turbidimeter with six structural elements; its method has seven steps. Two steps are the divisional's distinguishing additions over parent US 9,851,297: (i) activating the cleaning device if a contamination signal was generated; and (ii) re‑requesting the contamination test after cleaning finishes.

Observation: Every structural element and every method step of claim 1 is individually disclosed in the art of record. The claim is therefore a candidate for a KSR "predictable combination" rejection. The only element with no single squarely on‑point disclosure in the citation list is the specific placement of a diffuser (rather than a calibration standard) in a switchable test position between source and cuvette — and that gap is bridged by US 5,912,737's beam‑path diffuser and US 5,467,187's frosted‑glass standard.

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3. Specific proposed combinations

Combination 1 (primary): US 5,467,187 (Beers) + US 4,168,579 (Sato) + US 5,912,737 (Banerjee/Stream)

What each teaches.

• US 5,467,187 — automated, in‑situ recalibration of a nephelometer using a standard element physically reciprocated into and out of the beam by an actuator inside a cylindrical cuvette; derives a calibrated value by comparison against the standard; expressly recognizes that "contamination or deterioration of the optics/electronics" is a source of error, and lists as an object "to automatically clean the interior surface of a test fluid holder."
• US 4,168,579 — a turbidimeter with a cylindrical cell on the optical axis and a motor‑driven rotating brush that descends into the cell to wipe the inner surface, in a normal position that does not interfere with the beam, actuated on demand or periodically.
• US 5,912,737 — a turbidimeter calibration‑verification device that puts a diffuser in the light path and is tuned at manufacture to a fixed reference value (e.g., 0.5/1.0/20 NTU), thereby providing the memorized "reference light intensity" and the manufacturing‑time reference measurement recited in the claim.

Why a POSITA would combine (articulable rationale).

1. Same field, same problem, same result. All three address optical measurement of turbidity in a static cuvette and the need to keep the measurement accurate over time. KSR permits combination of references addressing the same problem.
2. Known technique applied to a known device for its established function. Using a switchable optical element (standard) to test the optical train (Beers) and using a rotating brush to remove the contaminant the specification itself identifies (Sato) yields only the predictable result of a cleaner, verified cuvette.
3. Explicit problem recognition and motivation in the art itself. Beers states the object of automatically cleaning the interior surface; Sato states the wiper may be operated "periodically or whenever the inner surface of the sample cell is smeared." That is the claim's "activate the cleaning device if a contamination signal has been generated," and it supplies the motivation directly.
4. "Clean‑then‑verify" is routine feedback control. Once a contamination signal triggers cleaning, re‑running the same test to confirm the cleaning worked is the natural, predictable next step (a closed‑loop maintenance routine) — well within the ordinary creativity of a POSITA and supported by Beers' continuous re‑verification per pulse cycle.
5. Substitution of the reference standard's form. Substituting a diffuser body (US 5,912,737) for the frosted‑glass/opaque standard of Beers, and locating it just upstream of the cuvette rather than inside it, is a simple substitution of one known element for another to obtain its known effect (diffuse illumination of the cuvette), a recognized KSR rationale.

Conclusion as to claim 1: Prima facie obvious under § 103 over Beers + Sato (optionally + Banerjee).

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Combination 2: US 2011/0043807 A1 (Endress+Hauser) + US 5,467,187 (Beers) + US 4,168,579 (Sato)

Why add US 2011/0043807. The patent's own Background admits US 2011/0043807 is prior art and criticizes it as requiring "two separate light sources and two separate light detectors," with "technical effort … relatively high," and as being confounded by "strong inhomogeneities of turbidity." Its disclosure is nonetheless highly material:

• It expressly states that its four‑beam alternating‑light evaluation "eliminate[s] … disturbances from fouling of the sensor" up to a degree — but that this same insensitivity means "self‑diagnosis … leads only to inexact results, since only larger disturbances … or strong foulings make themselves noticeable."
• It uses an additional monitor diode receiving light on a direct path that does not interact with the medium and checks the turbidity value's plausibility on that basis.

The motivation is supplied by the applicant's own admitted problem. The specification states the object is to provide "a simple device … and a simple method for detecting contamination," in contrast to the "relatively high" technical effort of US 2011/0043807. A POSITA reading US 2011/0043807's admission that its design is insensitive to small fouling — precisely the failure the applicant set out to fix — has a strong, explicit reason to adopt a more sensitive contamination test (the switchable diffuser of Beers) combined with the automated cleaner of Sato.

Caveat on this combination. The applicant's criticism in the Background is not a "teaching away" in the legal sense (it criticizes the reference's cost/complexity, not the operability of the claimed approach), so it does not rebut obviousness. Note also that under KSR a "teaching away" requires that the reference criticize, discredit, or otherwise discourage the claimed solution.

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Claim 2: adding the light‑source detector

Claim 2 adds a light‑source detector assigned to the diffuser body that directly receives the diffuse test light when the body is in the test position, and the step of comparing the measured source intensity with a reference source intensity.

• US 2011/0043807 A1 discloses exactly this architecture in substance: a monitor diode (13) that receives light directly from the LED on a path that does not interact with the measured medium, used for plausibility/diagnosis of the measurement. A POSITA combining 3807 with Beers would naturally position the monitor photodiode to view the diffuser body in its test position (the only object emitting light when the body is in the test position) — this is the predictable placement dictated by geometry.
• The reference‑detector‑for‑lamp‑drift function is also general knowledge corroborated by the art: HF Scientific's Micro 1000 documentation describes "a **reference detector that monitors the light output by the light source … used to generate a more accurate measure of turbidity should there be any fluctuation in lamp intensity (via voltage spikes or lamp ageing)." (Product documentation, not of record, but probative of the ordinary skill level.)
• Motivation: Beers expressly lists "light source aging, sensor deterioration" among the errors to be compensated. Monitoring the source with a dedicated detector to normalize the contamination test is the directly‑suggested remedy.

Conclusion: Claim 2 is obvious over Combination 1 or 2 further in view of US 2011/0043807 (monitor diode), and, independently, over routine reference‑detector practice.

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Claim 3: closed‑loop control of source intensity to the reference

Claim 3 adds driving the measurement source (via the light‑source detector) so its measured intensity equals the stored reference source intensity.

• This is a standard ratiometric/feedback (AGC) servo applied to a lamp/LED: a known technique used to hold illumination constant. Beers' microprocessor already normalizes measured signals to compensate for "deterioration of the electronics or … contamination." Going one step further to drive the source to the reference level (instead of arithmetically normalizing the readings) is the predictable, equivalent alternative — a classic KSR "known technique to improve a similar device in the same way."
• Motivation: Without equalizing source output, the claim's own comparison (test intensity vs. reference intensity) is confounded by lamp drift; equalizing it is the obvious way to make the comparison meaningful.

Conclusion: Claim 3 obvious over Combination 1/2 + Beers' normalization teaching (and/or the monitor‑diode feedback of US 2011/0043807).

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Claim 4: lamp‑lifetime signal from electrical energy vs. reference

Claim 4 adds comparing electrical energy used to generate the reference source intensity against an energy reference, issuing a "lifetime signal" if the difference exceeds a second threshold.

• This is the weakest of the four claims to attack on the art of record, and I flag it as such. None of the references in the patent's "Citations (26)/Patent Citations (28)" tables squarely teaches end‑of‑lamp‑life detection by comparing drive energy/power to a stored reference. At most the field recognizes "light source aging" and "sensor deterioration" as error sources to be compensated (Beers; US 2011/0043807's "component fluctuations").
• A defensible § 103 position still exists, but it rests on general knowledge / obvious design, not on a single reference: (a) the claim presupposes the feedback loop of claim 3 (which itself provides the measured source intensity needed to know when more electrical energy is required); (b) measuring electrical drive power to a light source as an indicator of its health/wear is a routine, well‑known diagnostic in lamp‑driven instrumentation; and (c) the claim recites only the prediction of a status signal from that comparison — a "predictable variation" of a known monitoring function. That said, an examiner or court may want an explicit secondary reference (e.g., a lamp‑end‑of‑life or "lamp fail" detection patent) to make the rejection clean.
• Recommendation: Pair claim 4 with an additional § 102/§ 103 reference directed to lamp‑wear/lifetime detection via drive‑current or drive‑power monitoring — that is the missing keystone.

Conclusion: Claim 4 — potentially obvious, but not adequately supported by the prior art of record; requires supplementary art.

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4. Summary table

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5. Objective indicia (Graham factor iv)

No evidence of unexpected results, long‑felt need, commercial success, or copying is of record or was located. Notably, the specification itself frames the invention as a simpler alternative to a known approach rather than as an unexpected technical advance, and does not assert any surprising result from the clean‑then‑retest loop. A nexus between any secondary consideration and the specific claimed combination would be difficult to establish. (As noted in the earlier litigation section, no assertion or market‑based secondary‑considerations record surfaced.)

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6. Caveats and confidence

1. Characterization of US 5,467,187 and US 4,168,579 rests on their published text as retrieved (Google Patents / FPO). The "frosted‑glass" description of the Beers standard appears in a Russian‑language analysis of that patent (RU 2 559 164 C1); the English language of US 5,467,187 as retrieved describes a "transparent … calibration element" with sealed standard compartments. If the Beers standard is not actually diffusing, the "diffuse test light" limitation is supported only by US 5,912,737's light‑shaping diffuser, which is still in the beam path of a turbidimeter — verify the Beers disclosure against the granted PDF before relying on the "diffuser" reading.
2. CN 202,974,867 U ("Turbidity meter with cleaning function") appears in the family‑citation table and would be directly relevant to claim 1's cleaning element, but my search budget was exhausted before I could verify its disclosure. Its 2013‑06‑05 publication date makes it qualifying § 102 prior art — worth pulling.
3. US 9,182,344 B1 and US 9,329,195 B2 (from the "Cited By" tables) are not § 102 art to these claims (post‑date the 2013‑09‑30 priority) and should not be used.
4. Claim 4 is the realistic point of novelty. I could not locate a reference of record teaching energy‑comparison‑based lamp‑lifetime signaling. Absent such a reference, claim 4 is the claim most likely to survive a § 103 challenge.
5. No contradiction was found between this analysis and the two earlier sections. One cross‑reference worth noting: this divisional's added cleaning‑and‑retest subject matter is not in the parent US 9,851,297's claims as described earlier, so no obviousness‑type double patenting issue arises between them on these facts — but the two share a priority date, so neither is prior art to the other.