US 10775341

I'll run a few targeted searches for this patent number, then summarize.

Let me check for any litigation or CAFC activity, and verify the bibliographic data.

One more check on litigation/PTAB records.

US 10,775,341 — Record Check & Summary

Search coverage / confidence caveats

• I could not directly query USPTO PatentCenter, PAIR, or the CAFC docket system with these search tools; results below come from patent aggregators (Google Patents, Justia) plus general web search for litigation.
• No CAFC 2026 docket entry, district-court docket, or PTAB proceeding referencing 10,775,341 was found. Repeated queries for "10775341" / "10,775,341" combined with "Federal Circuit," "CAFC," "docket," "litigation," and "infringement" returned only unrelated Federal Circuit matters (e.g., 2025-1617, 2026-1420, 2025-1968, HMTX/Section 301, Mylan/Bausch IPR2022-00722, 10x Genomics). Treat "no litigation found" as absence of evidence in these searches, not a verified negative.
• The most substantive confirmation of bibliographic data came from Justia's patent record and the Google Patents full text supplied in the prompt (authoritative for claim language).

Bibliographic data

Note: Justia also lists a "Current U.S. Class: With Fluid Flow Deflector (374/138)" for this record. That is almost certainly an artifact of Justia's class-mapping display rather than a meaningful classification for a zirconia NOx sensing element; I flag it rather than endorsing it.

Abstract (as issued)

In a sensor element 101, oxygen contained in a gas to be measured introduced into a first internal space 20 through a first diffusion control part 11 is pumped out by applying voltage between an inner pump electrode 22 and an outer pump electrode 23. After the oxygen is pumped out, NOx in the gas to be measured generates oxygen by being reduced by a measurement electrode 44. This oxygen is pumped by applying voltage between the measurement electrode 44 and the outer pump electrode 23. On the basis of current generated according to the amount of oxygen thus pumped, the NOx gas concentration is calculated. A slit width of the first diffusion control part 11 on an entrance side is larger than a slit width on an exit side.

The technical problem being solved

The patent frames the problem as soot/particulate matter (PM) in exhaust gas adhering to the entrance of the slit-shaped diffusion-control region (e.g., gas introduction portion 310 in the prior-art FIG. 10 structure). Entrance-region temperatures (~400–600 °C) are too low to burn off the deposits. Once the entrance is partially blocked, the amount of gas entering the internal space is restricted and the reported gas concentration no longer matches the actual concentration. The stated remedy is a "width transition slit": a wide entrance that lets solids pass through and travel into the slit, where they lodge at the narrow portion and are burned away because that region is heated to a higher temperature (the specification gives, for example, 600 °C or more) by the heater.

Plain-language overview of each independent claim

Claim 1 — the sensor element (apparatus).
A layered solid-electrolyte gas sensor element in which:

• The base is built from multiple stacked oxygen-ion-conductive solid electrolyte layers plus a spacer layer sandwiched between two of them.
• One or more slits sit at the entrance side of an internal space. Critically, the claim requires that the entirety of each slit is formed directly between one of the solid electrolyte layers and a portion of the spacer layer, as measured in the layer-stacking direction — i.e., the slit is a gap in the stack whose width is a stacking-direction dimension. (This "entirety… directly between… in a stacking direction" language is a narrowing limitation added in prosecution relative to the published application, and it is the aspect a validity or infringement analysis would turn on.)
• Inner and outer pump electrodes (one inside the base, one outside) pump oxygen out of the internal space to the external space.
• An inner measurement electrode, working with the outer pump electrode, decomposes a target gas component (NOx) remaining after the oxygen is pumped out and pumps the resulting oxygen to the external space.
• A heater heats the base.
• At least one slit is a "width transition slit" whose slit width, measured in the stacking direction, is larger on the entrance side than on the exit side.

Claim 5 — the manufacturing method (expressly a method "of manufacturing the sensor element of claim 1," so it inherits claim 1's structural limits):

• (a) prepare multiple green sheets, each of oxygen-ion-conductive solid electrolyte;
• (b) form electrode precursors (pump and measurement electrode precursors) on at least one green sheet, and form disappearing material layers on surfaces of the two green sheets that will face the internal space — the disappearing material burning away during firing and being thicker toward the entrance of the internal space;
• (c) stack the sheets so that a slit forming portion of solid electrolyte is held between the disappearing material layers, and fire at a predetermined temperature so the sheets and the slit forming portion sinter while the disappearing material vanishes — leaving the width transition slit.
  The specification adds the practical benefit that the widened entrance-side slit prevents the unsupported entrance-side portion of the green sheet (portion 105a, later the first bridge portion 5a) from sagging during firing and closing the slit.

Claim 7 — the gas sensor.
A gas sensor including the sensor element according to claim 1. It is purely an incorporation claim; scope tracks claim 1 plus whatever else a "gas sensor" assembly entails (housing, etc.), as the specification describes.

Dependent claims (for context): claim 2 — entrance end portions of the width transition slit are wider than the entrance center portion, with at least the end portions wider than the exit-side width; claim 3 — the slits are plural; claim 4 — two slits on opposite sides of a layer portion, where the slit on the side closer to the heater is the width transition slit; claim 6 — a two-step disappearing-layer printing process (a first layer at least as long as the slit forming portion in the depth direction, then a second, shorter layer on top of the first layer or on the slit forming portion).

Note on claim-vs-summary wording

The published summary in the patent document describes claim 4's concept loosely as "two slits respectively provided on sides close to and far from the heater, and the slit close to the heater may be the width transition slit." The issued claim 4 is phrased in terms of "opposite sides of a portion of a layer of the base… a second side that is closer to the heater… and at least the slit on the second side… is the width transition slit." For any claim-charting or infringement purpose, use the issued claim language, not the summary paragraph.

Bottom line

This is an NGK Insulators zirconia-based NOx sensor element patent (priority JP 2016-061366) covering a diffusion-control slit whose cross-section narrows from the gas entrance toward the internal space, so that soot passes the cooler entrance and burns off in the hotter, heater-adjacent narrow region — plus the corresponding disappearing-layer manufacturing method and a gas sensor incorporating the element. I found no evidence of any 2026 CAFC appeal, district-court case, or PTAB challenge involving this patent in the searches run, but I could not query the courts' docket systems directly, so that should be independently verified against PACER/Docket Navigator and the CAFC docket if a definitive litigation-clearance answer is needed.

I'll search for litigation involving US patent 10775341.

Let me search more targeted litigation databases.

Let me do more targeted searches with the exact patent format.

Search Results: Litigation for U.S. Patent No. 10,775,341

No litigation involving U.S. Patent No. 10,775,341 (US10775341B2) was found.

I searched litigation-focused sources (Unified Patents litigation/PTAB portal, PACER- and CourtListener-derived materials, and general web search) using the exact identifiers "10775341," "10,775,341," and "US10775341B2" in combination with litigation terms. None of the returned records pertain to this patent.

Important caveats on my search

• No matching hits were returned at all for this specific number. The database-style searches did not surface any district court complaint, CAFC appeal, ITC action, or PTAB proceeding asserting or challenging U.S. 10,775,341.

• I deliberately did not return "similar number" results, per your instruction. Several documents in the results referenced a "'341 patent," but each is a different patent that merely shares the trailing digits:

  • U.S. 10,375,341 — asserted in Maxell v. TCL and challenged in a TCL IPR petition (video display / bidirectional wireless communication).
  • U.S. 9,035,341 — asserted in Samsung Electronics Co., Ltd. v. Technical Consumer Products, Inc. (LED lighting).
  • The AbbVie " '341 patent" in the AbbVie v. Hetero / Micro Labs ANDA suits (QULIPTA®) — a different patent number entirely.

  None of these is U.S. 10,775,341, and none should be attributed to it.

Patent context (relevant to likelihood of litigation)

• Patent: US 10,775,341 B2 — "Sensor element, manufacturing method therefor, and gas sensor"
• Assignee: NGK Insulators, Ltd.
• Inventors: Akari Tominaga; Hirohito Kiyota
• Priority date: 2016‑03‑25 (JP 2016‑061366); Filed: 2017‑03‑10; Granted: 2020‑09‑15
• Family: JP 6805033 B2; DE 102017002308 A1
• Status: Active, adjusted expiration 2037‑12‑31

NGK Insulators is predominantly a defendant-side participant in U.S. patent matters historically (e.g., it was a defendant in the In re: Automotive Parts Antitrust Litigation, MDL No. 2:12‑md‑02311 (E.D. Mich.), which involved antitrust claims — including ceramic-substrate price-fixing in which NGK settled — not patent infringement of this patent). No affirmative assertion of U.S. 10,775,341 by NGK, nor any IPR/PGR challenging it, appeared in my searches.

Bottom line

Based on the searches performed, there are no known U.S. litigation proceedings (district court, CAFC, ITC) or PTAB proceedings involving U.S. Patent No. 10,775,341.

Confidence and limitations: I have moderate-to-high confidence that no prominent litigation exists, since a reasonably well-covered case would typically appear in these sources. However, I cannot rule out (a) very recent filings not yet indexed, (b) state-court or foreign actions, or (c) cases where the patent number is mentioned only within a larger case record. For definitive confirmation I would recommend querying PACER directly (search by patent number) and the USPTO Patent Center / PTAB (Patent Trial and Appeal Board) docket, as well as Lex Machina / Docket Navigator, which index patent numbers at the case level. If you can provide a party name or product category of interest (e.g., a specific sensor supplier), I can run a narrower, more targeted search.

I'll verify the ODP result against public sources before finalizing.

No hits tying the patent to any trial. Let me run a couple more targeted checks.

One last verification pass on litigation/assertion and any Unified Patents activity.

Proceedings overview

Total AIA trial proceedings on US 10,775,341: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM filings for this patent, and my independent web checks (PTAB-related dockets, NGK party searches, patent-number and patent-title searches, and defensive-aggregator activity) surfaced nothing tying US 10,775,341 to any Board proceeding. There is therefore no breakdown by status to give — no claims invalidated, none sustained in an FWD, no settlements, no institution denials.

Bottom-line defensive posture: the patent is untested at the PTAB, which cuts both ways. On the positive side for a defendant, Patent Owner NGK Insulators forfeits nothing procedurally — there is no § 315(e)(2) estoppel wall, and the full prior-art space is open to you. On the negative side, NGK has never had to defend these claims in a validity trial, so there is no petitioner-favorable record, no claim constructions, and no Board credibility findings to borrow. A defendant here is buying an expensive first-mover ticket: you would be the first to litigate validity of a patent that has been on file since 2017 with no challengers.

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Proceedings overview (detail)

No proceedings to enumerate. The structured "PTAB proceedings on file" block returned an empty result set, and nothing was found in public sources to fill that gap. Per the operating instruction, the default is "no PTAB activity on file," and that default is confirmed here.

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Strategic summary

Claim status — all claims untested. US 10,775,341 issued 2020-09-15 from Application 15/455,180, filed 2017-03-10, claiming priority to JP 2016-061366 (2016-03-25). It has 7 claims: independent claim 1 (sensor element with a width-transition slit whose width is larger in the stacking direction on the entrance side than the exit side), dependent claims 2–4, independent claim 5 (method of manufacturing, incorporating claim 1 by reference), dependent claim 6, and independent claim 7 (gas sensor including the claim-1 element). Because no IPR has run, every one of claims 1–7 remains in force as issued — none canceled, none confirmed by the Board, all untested. The patent is currently recorded Active with an adjusted expiration of 2037-12-31.

Estoppel landscape. There is no § 315(e)(2) estoppel in play at all — no petitioner has ever appeared, so nobody is barred and no ground has been "raised or reasonably could have raised." Practically, that means a defendant today has the complete menu available: § 102 anticipation and § 103 obviousness over any printed publication or patent, § 112 written description / enablement / indefiniteness theories, and even a § 101 challenge if the claim language supports it. The § 102/§ 103 art space is especially open on a claim-1 limitation this specific — "an entirety of each of the one or more slits being formed directly between one of the plurality of oxygen-ion conductive solid electrolyte layers and a portion of the spacer layer in a stacking direction." That narrowing language was materially added during prosecution (it is absent from the published 2017-09-28 application text), which signals exactly where the examiner drew the line and where a validity attack should focus.

Pattern signals. NGK Insulators is a large, patent-savvy ceramics/automotive supplier and a frequent patent owner; it litigates selectively. The notable absence of any IPR against this patent is itself a data point: well-asserted patents in the emissions-sensor space (where Bosch, Denso, Continental, NGK all hold portfolios) tend to attract PTAB challenges once a commercially significant dispute arises. The absence of any proceeding suggests the '341 patent has not yet been asserted in a substantial US infringement campaign — or, if it has, that defendants have chosen district-court invalidity or design-around over an IPR. I found no defensive aggregator (Unified Patents or similar) involvement, no Federal Circuit appeal, and no PTAB appeal of any kind. I also want to flag one thing I did see and could not connect: NGK Insulators has co-pending US applications titled "SENSOR ELEMENT" (App. Nos. 18/602,469 and 18/602,459) currently in Final Rejection, and family members JP6805033B2 and JP7470610B2. Those are ordinary prosecution matters, not AIA trials, and none of them is this patent — do not treat them as PTAB activity.

Caveat on confidence. I searched PTAB-facing sources and open web indexes, not the PTAB E2E system directly with a party-name docket pull, and ODP ingest can lag. If you are on a short fuse, pull the patent's "Patent Trial and Appeal Board" tab on PatentCenter and run a party-name search for "NGK Insulators" on PTAB E2E before filing anything that assumes a clean history. My conclusion is that no proceeding exists, but the negative is worth a five-minute confirmation from the primary source.

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Recommended next steps

• If you are a defendant and this patent is being asserted against you: there is no FWD to cite and no canceled claims to hide behind. Your opening brief should not claim "claims 1–5 have been canceled" — they have not. Build your invalidity case from scratch, and prioritize the prosecution-history narrowing of the "entirety of each of the one or more slits … directly between … solid electrolyte layer and … spacer layer in a stacking direction" limitation in claim 1, since that is the examiner's stated line of distinction. Because claim 5 (method) and claim 7 (gas sensor) both depend from claim 1's structure, a successful attack on claim 1's slit-placement limitation would cascade to all three independent claims.
• If you are contemplating an IPR: you are the first mover, with zero estoppel risk from prior petitioners, but also no roadmap. Expect the Board to construe the stacking-direction slit limitation carefully, and expect NGK to lean on the prosecution-history record and on the PTL citations (JP 3798412 B, JP 2011-102797 A) that were already before the examiner. Note the § 315(b) one-year bar from service of any complaint — if suit has been filed against you, calendar it immediately.
• If there is no active proceeding and no assertion: say so plainly internally. The correct read is that US 10,775,341 is an unexercised, un-IPR'd patent with all seven claims intact and roughly 11 years of adjusted term remaining (to 2037-12-31). It is a live risk, not a paper tiger, and the absence of PTAB activity means no one has yet done the validity work for you.

Sources checked / to verify against primary records:

• USPTO PatentCenter for US 10,775,341: https://patentcenter.uspto.gov (party-name docket pull for "NGK Insulators")
• PTAB E2E (AIA trial docket): https://ptacts.uspto.gov/ptabweb/
• Google Patents record (full text, claims, family, and cited art used above): https://patents.google.com/patent/US10775341/en
• CourtListener (for any parallel district-court or CAFC docket): https://www.courtlistener.com

I'll research the assignment record for this patent through the available sources.

Let me try more targeted searches for the specific assignment record.

Let me make one more attempt to locate the specific reel/frame record before finalizing.

Ownership-Chain Reconstruction — U.S. Patent No. 10,775,341 (US10775341B2)

Source note / limitation up front: My tooling here is general web search only — I could not directly query the USPTO Assignment Center (assignmentcenter.uspto.gov) or the legacy assignment index (assignment.uspto.gov/patent/index.html) by patent number, so no reel/frame number and no correspondent-of-record could be confirmed from the primary source. The single post-filing ownership event below is drawn from the authoritative Google Patents legal-events table in the supplied record. Any reel/frame or correspondent detail should be verified directly at USPTO Assignment Center / legacy search.

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Inventors

Pattern notes: Both named inventors are assignors to the same corporate assignee, which is the ordinary signature of employee-inventor-to-employer assignment — not a red flag. I found no evidence that either inventor departed NGK within 12 months of filing, and no evidence of inventor-level transfers to any third party. (Employment is a presumption from the NGK-context of the art and the assignment events; I could not independently confirm either inventor's employment contract or current status, so treat "employer at filing" as probable, not verified.)

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Original assignee

NGK Insulators, Ltd. (2-56 Suda-cho, Mizuho-ku, Nagoya, Aichi 467-8530, JP) — the entity named on the issued patent.

• Primary line of business: Advanced ceramics manufacturer. Relevant divisions include automotive/ceramic sensor elements (the field of this patent), NAS battery systems, power-transmission insulators, and semiconductor-manufacturing equipment components. Publicly traded on the Tokyo Stock Exchange (a long-established operating company, not a holding vehicle).
• Does it ship a product embodying the claims? Yes, highly likely. NGK is a major OEM supplier of zirconia (ZrO₂) solid-electrolyte NOx / exhaust-gas sensor elements for automotive aftertreatment. The claimed "width transition slit" is an internal geometric feature of exactly that class of product, so the patent is consistent with NGK's commercial sensor-element line. (I did not locate a product datasheet that maps part numbers to this specific claim, so this is an informed judgment, not a documented mapping.)
• Current status: Operating — no evidence of acquisition, dissolution, or bankruptcy in the searches performed.

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Assignment timeline

Only one ownership event appears in the record for this patent. It is the inventor-to-employer assignment; there are no post-issuance, security-interest, or change-of-name recordings.

• Executed: not surfaced (execution date not available in my sources) / recorded 2020-08-06 — Reel not retrievable (Assignment Center not directly queryable)
  • Conveyance: Assignment — "Assignment of Assignors' Interest" (as labeled in the record)
  • Assignor: Hirohito Kiyota; Akari Tominaga (joint inventors)
  • Assignee: NGK Insulators, Ltd.
  • Correspondent: Not available — could not be retrieved from the assignment document. No recurrence to assess.
  • Context: Internal/confirmatory assignment — employee inventors conveying rights to their employer; recorded ~5 weeks before issuance (patent granted 2020-09-15).

Flag on timing (worth verifying): The application was filed 2017-03-10, but this assignment was not recorded until 2020-08-06 — a ~3.5-year lag, landing just before grant. That is consistent with a confirmatory / curative assignment recorded in anticipation of issuance (e.g., where the assignee was already prosecuting the application as applicant and the paper assignment was perfected late), rather than a mid-life transfer. Because I could not pull the reel/frame or the execution date, I cannot distinguish "late-recorded original assignment" from "confirmatory second assignment." This is a mechanical-record question, not an ownership-substance question — NGK has been the owner throughout.

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Timeline diagram

timeline
    title Ownership of US 10775341
    2016 : JP priority application filed
    2017 : US application filed by NGK
    2020 : Inventors assign rights to NGK
         : Patent issued to NGK Insulators

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NPE / troll-pattern signals

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Verdict

Operating-company assertion.

Justification (2–3 sentences): The sole recorded ownership event is the inventors' assignment of rights to NGK Insulators, Ltd. (recorded 2020-08-06, i.e., to the operating manufacturer, ~5 weeks before the 2020-09-15 grant), and nothing in the chain ever leaves NGK. NGK is a publicly traded, product-shipping ceramics manufacturer whose zirconia NOx sensor elements occupy exactly the technical field of the claims, and there is no shell-LLC transfer, known-asserter link, cascading conveyance, or bankruptcy fire-sale anywhere in the record (reel/frame unrecognized — see caveat). No litigation naming this patent was found, so this is best characterized as an operating-company-held patent rather than an active assertion campaign; the "assertion" label reflects ownership/practice by an operating company, not a documented suit.

Caveat on data completeness: I could not directly query the Assignment Center, so the reel/frame, execution date, and correspondent of record are unverified, and the possibility of a very recent or unindexed recording cannot be excluded. Verify at the USPTO Assignment Center or legacy assignment search by patent number 10,775,341.

Bottom line: No NPE / patent-troll signals are present. This is a standard employee→employer assignment to NGK Insulators of a zirconia NOx sensor-element patent; ownership has never moved to a licensing entity.

I'll verify the citation records for US 10,775,341 against the USPTO and other sources before analyzing anticipation.

Let me verify the remaining cited references, particularly any that might disclose varying-width diffusion slits.

Scope, sources, and method

Important limitation up front: I could not open the USPTO Patent Center / Patent Application Information Retrieval (PAIR) or the examiner's official "References Cited" listing directly with the tools available. The citation set below is taken from the authoritative full text you supplied (the Google Patents record for US 10,775,341 B2, which reproduces the front-page "Citations" and "Patent Citations" lists), supplemented by targeted web searches to characterize the individual references. Where I characterize a reference's disclosure, I say how confident I am. I did not retrieve the complete specification of every cited document, so the § 102 characterizations for the less-central items are provisional and should be confirmed against the full texts.

Legal standard applied. A reference anticipates a claim under 35 U.S.C. § 102 only if it discloses every element and limitation of that claim, arranged as in the claim, in a single document (or an explicit single-source disclosure). References that disclose the general architecture but not the point of novelty are not anticipating; they are at most § 103 combination material. Because claims 2–4 and 6 are dependent, they cannot be anticipated by anything that does not first anticipate their parents (claims 1 and 5).

What actually has to be shown to anticipate. Reviewing the issued claims (reproduced in your earlier sections):

• Claim 1 requires (i) the layered base of stacked solid-electrolyte layers plus a spacer layer; (ii) one or more slits at the entrance side of an internal space, the entirety of each slit formed directly between a solid-electrolyte layer and a portion of the spacer layer, measured in the stacking direction; (iii) inner/outer pump electrodes; (iv) an inner measurement electrode operating with the outer electrode; (v) a heater; and (vi) at least one slit being a "width transition slit" whose width in the stacking direction is larger on the entrance side than on the exit side.
• Claim 5 (method) requires green sheets of oxygen-ion-conductive solid electrolyte; electrode precursors; disappearing material layers on the two green sheets facing the internal space, thicker toward the entrance; stacking so a slit-forming portion is held between the disappearing layers; and firing until the disappearing layers vanish to leave the width-transition slit.
• Claim 7 is a gas sensor that simply includes the claim-1 element — its scope rises and falls with claim 1.

The feature that distinguishes this patent from the cited art is the width-transition slit (w1 > w2) and the entrance-thickened disappearing-layer method of making it. Nothing in the citation list that I was able to characterize appears to disclose that feature; the cited documents supply the well-known NGK NOx-sensor architecture (internal spaces, diffusion-control slits, pump/measurement cells, heater) or are peripheral. I detail that reference by reference below.

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The cited references (§ 102 analysis)

A. Same-assignee / sensor-architecture art (the genuinely relevant references)

1. US 5,672,811 A — "Method of measuring a gas component and sensing device for measuring the gas component" — NGK Insulators, Ltd. (Kato et al.)

• Priority 1994-04-21; published 1997-09-30. (Family: EP 0678740; continuations US 6,076,393 and US 6,196,053; JP counterpart cited as JP 2004-239916 A.)
• Description: The foundational layered zirconia NOx-sensor disclosure — measurement gas is drawn from an external space into a first internal space under a first diffusion resistance, oxygen is pumped to produce an atmosphere that does not decompose the target component, the atmosphere passes into a second internal space under a second diffusion resistance, the component is reduced/decomposed, and the resulting pumping current is measured. Discloses inner/outer pumping electrodes, a reference electrode/channel, and (in the family) a heater.
• § 102: Discloses elements (i), (iii), (iv), (v) and the slit-based diffusion-resistance concept of claim 1, but I found no disclosure of a slit whose width is larger on the entrance side than the exit side (the reference speaks of diffusion resistance/cross-section, not a tapering slit). It therefore does not anticipate claim 1 (and thus not claims 2–4 or 7). High confidence it is the closest architectural antecedent but not an anticipatory reference.

2. JP 2004-239916 A — "NOx sensor" — NGK Insulators Ltd.

• Priority 1994-04-21; published 2004-08-26.
• Description: Japanese publication in the same family/lineage as US 5,672,811 (cited in the background as part of the "conventional art" family). Same layered NOx-sensor architecture.
• § 102: Same analysis as US 5,672,811 — supplies the environment, not the width-transition slit. Does not anticipate claims 1/5/7. Medium confidence pending full-text review.

3. US 6,355,152 B1 — "Gas sensor and nitrogen oxide sensor" — NGK Insulators, Ltd.

• Priority 1998-07-08; published 2002-03-12. (EP 0971228 A2; also US 6,527,929, US 6,770,181, US 7,445,700 in the family.)
• Description (verified): Discloses first diffusion-rate-determining section(s) formed as slits (30, 32) each having a laterally extending aperture at a front end portion of a spacer layer contacting a solid-electrolyte layer, with the aperture extending "with an identical aperture width up to the first chamber" and a vertical dimension ≤ 10 μm; the slits have a "substantially identical cross-sectional configuration." A buffer space is placed between the gas-introducing port and the diffusion-rate-determining means.
• § 102: This is the most instructive negative example. It expressly teaches constant-width slits, the opposite of the width-transition slit. It is highly relevant prior art (same assignee, same slit-in-spacer architecture, even the ≤10 μm slit-size range) but does not anticipate claim 1. It is the strongest candidate for a § 103 combination against the width-transition feature, though the Applicant appears to have distinguished over exactly this family during prosecution (the "entirety … directly between … in a stacking direction" limitation in issued claim 1 reads like a response to it). High confidence.

4. US 2005/0211554 A1 — "Gas sensor element" — NGK Insulators, Ltd.

• Priority 2004-03-29; published 2005-09-29.
• Description (verified): Laminar sensor element with first and second solid-electrolyte layers sandwiching a spacer layer; buffer space, first space, second space; first, second and third diffusion-controlling passages in the form of slits; a first partition wall integrally fixed to the first solid electrolyte layer and cooperating with the second solid-electrolyte layer to define the first diffusion-controlling passage; inner/outer pumping electrodes; a heater layer. Directed at reducing cracking.
• § 102: Discloses the claim-1 architecture and the "slit between a solid-electrolyte layer and a spacer/partition wall" geometry with unusual closeness. But the passage widths are not taught as wider at the entrance than the exit. Does not anticipate claim 1 (or 2–4, 7). Medium-high confidence; a full-text check for any tapered/stepped slit is worth doing.

5. US 2009/0242404 A1 — "Gas sensor" — NGK Insulators, Ltd.

• Priority 2008-03-28; published 2009-10-01.
• Description (verified): NOx sensor with two gas inlets (openings as horizontally long slits), buffer space, first and second internal spaces, and first and second diffusion control parts each provided as two horizontally long slits arranged one above the other; corresponds to US 2011/0083490-family and EP 2312306.
• § 102: Discloses the multi-slit, slit-in-spacer diffusion-control structure of claim 1 (elements i, ii in part, iii–v). No taper. Does not anticipate claims 1/5/7. Medium confidence.

6. US 2011/0233060 A1 — "Gas sensor" — NGK Insulators, Ltd.

• Priority 2010-03-29; published 2011-09-29.
• Description: NGK NOx sensor element with first, second and fourth diffusion control parts formed as horizontally long slits; disclosure of slit height relative to electrode film thickness (per the related EP 2312306 discussion found in search).
• § 102: Same family of architecture; no width-transition teaching. Does not anticipate claims 1/5/7. Medium confidence.

7. US 2013/0255352 A1 — "Method for manufacturing sensor element for use in gas sensor, inspecting electrical characteristics of sensor element, and pre-treating sensor element" — NGK Insulators, Ltd. (granted as US 9,229,047).

• Priority 2012-03-29; published 2013-10-03.
• Description: Manufacturing method for a layered oxygen-ion-conductive sensor element with an internal space and inner/outer electrodes; directed to electrode stabilization/inspection rather than slit geometry.
• § 102: Relevant to the claim-5 method environment (green-sheet lamination, electrode formation, firing) but does not disclose disappearing material layers whose thickness increases toward the entrance. Does not anticipate claim 5 (and thus not claim 6). Medium-high confidence.

8. JP 2011-102797 A — "Gas sensor and method for manufacturing sensor element" — NGK Insulators Ltd. (this is PTL 2 named in the '341 background; US equivalent US 2011/0147214 A1).

• Priority 2009-10-15; published 2011-05-26.
• Description: Gas sensor with a layered element and a method for its manufacture; describes the gas inlet → diffusion control → buffer → internal-space pathway. Cited by the Applicant in the background as representative conventional art.
• § 102: Most relevant to claim 5 because it is a manufacturing method for a substantially similar element, but I found no teaching of entrance-thickened disappearing layers that burn out to leave a width-transition slit. Does not anticipate claim 5; medium confidence (full-text check recommended, since it is the closest method reference).

9. US 2011/0174049 A1 — "Inspection apparatus for sensor element, and method for inspecting electrical characteristics of sensor element" — NGK Insulators, Ltd.

• Priority 2010-01-18; published 2011-07-21.
• Description: Post-manufacture inspection/testing of sensor elements; not about slit geometry.
• § 102: Not anticipatory of any claim. Relevant only as evidence of the ordinary skill/background of layered sensor-element manufacture. High confidence it is non-anticipatory.

B. External (Bosch) sensor-element art

10. US 2007/0108049 A1 — "Sensor element" — Thomas Wahl (Robert Bosch).

• Priority 2003-09-29; published 2007-05-17.
• Description: Bosch planar exhaust-gas sensor element with a diffusion barrier/porous layer over an internal cavity; typically a resistive/wide-band or NOx planar element. I could not retrieve sufficient full text in the available searches to fix its slit geometry.
• § 102: Listed as examiner-cited, so presumably relevant to the layered-element/diffusion-barrier concept. My working conclusion is that it does not anticipate claim 1 because there is no indication it teaches a width-transition slit; but I flag low-to-medium confidence on this one and recommend review of its full text.

11. US 2008/0282773 A1 — "Device for passing through a gas mixture" — Andreas Varesi (Robert Bosch).

• Priority 2005-11-23; published 2008-11-20.
• Description: A gas-passage/duct structure for exhaust sensors (protecting an element), not a layered zirconia sensing element per se.
• § 102: On the face of the title/subject matter it is not anticipatory of claim 1's structurally specific width-transition slit. Low-to-medium confidence; verify against full text if a formal invalidity position is needed.

C. Peripheral references (examiner-cited; not anticipatory of the point of novelty)

12. US 6,322,247 B1 — "Microsensor housing" — Honeywell International Inc.

• Priority 1999-01-28; published 2001-11-27.
• Description: Housing/packaging for a microsensor (e.g., a micro-hotplate gas sensor), not a layered solid-electrolyte NOx element.
• § 102: Not anticipatory of the width-transition-slit subject matter; very low relevance. High confidence.

13. US 6,361,206 B1 — "Microsensor housing" — Honeywell International Inc.

• Priority 1999-01-28; published 2002-03-26 (sibling of the above).
• § 102: Same as #12 — housing art, not anticipatory. High confidence.

14. US 2003/0172741 A1 — "Sampling system for exhaust gas sensors and method of using same" — Michael-Rainer Busch.

• Priority 2002-01-29; published 2003-09-18.
• Description: Exhaust-gas sampling/protection system (e.g., a shield/sampling tube) upstream of a sensor.
• § 102: Not anticipatory of the internal slit geometry. High confidence. (It may be relevant background to the soot-deposition problem the '341 patent addresses.)

15. US 2017/0261463 A1 — "Gas sensor" — Denso Corporation.

• Priority 2014-09-16; published 2017-09-14.
• Description: Denso gas sensor; examiner-cited. Its effective filing date (2014-09-16) is before the '341 priority date (2016-03-25) but it published after it, so it is a candidate only under § 102(a)(2) (as a U.S. application publication effective as of a pre-priority filing date), not § 102(a)(1)/(b).
• § 102(a)(2): I could not retrieve enough of its disclosure to confirm whether it teaches a tapered/width-transition diffusion slit. Flag as unresolved; if it does disclose a variable-width slit, it would be the most dangerous cited reference. Recommend full-text review before relying on my "not anticipatory" default.

D. "Family cites" (applicant/third-party family references) — anomalies to flag

• JP 6,498,985 B2 (priority 2014-03-31; NGK) — sensor element/gas sensor; plausibly related background.
• JP 6,367,659 B2 (priority 2014-09-18) — titled "Power transmission shaft and vehicle propeller shaft." This is almost certainly a mapping error in the aggregator's "family cites" table; a propeller-shaft patent has no bearing on a zirconia NOx sensing element. I flag it rather than treat it as prior art. Do not cite it.

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Bottom line

• No reference in the '341 citation list, as I was able to characterize it, anticipates independent claims 1, 5, or 7. The cited documents overwhelmingly disclose the generic NGK layered NOx-sensor architecture (gas inlet → slit-shaped diffusion control → buffer/internal spaces → pump and measurement cells → heater) and the generic green-sheet lamination method — i.e., the environment the '341 invention improves upon — but not the width-transition slit (w1 > w2) or the entrance-thickened disappearing-layer method that are the point of novelty.
• The most relevant prior art (best § 103 combination candidates) are, in order:
  1. US 6,355,152 B1 / US 7,445,700 / EP 0 971 228 (NGK) — same slit-in-spacer architecture and even the ≤10 μm slit dimension, but expressly constant-width slits ("identical aperture width").
  2. US 2011/0147214 A1 / JP 2011-102797 A (NGK; PTL 2) — closest manufacturing-method reference for claim 5, but no disappearing-layer thickness gradient.
  3. US 2005/0211554 A1 and US 2009/0242404 A1 (NGK) — slit/partition-wall diffusion-control geometry closest to claim 1's structural language.
  4. US 5,672,811 (NGK; PTL 1 lineage) — foundational NOx-sensor architecture.
• Watch items requiring full-text verification before any formal validity opinion: US 2017/0261463 A1 (Denso) — the only cited reference whose pre-2016 effective date could make it § 102(a)(2) art; and the two Bosch references (US 2007/0108049 A1, US 2008/0282773 A1), for which I could not confirm slit geometry.

Confidence and caveats

• Bibliographic data (numbers, dates, titles, assignees) come from the patent's own front-page citation lists and the searches summarized above; I could not independently re-verify every entry against the USPTO Patent Center. Treat any single date as the aggregator's value, not a legal conclusion.
• All "does not anticipate" statements rest on my not finding the width-transition feature in the retrieved material for that reference. For the three items flagged above (Denso '463; Bosch '049 and '773), a direct full-text review against claims 1, 5 and 7 is required to convert "not found" into "confirmed absent."
• Per your standing instruction, I have not auto-corrected any identifier: e.g., the trailing "341" numbers in unrelated cases (U.S. 10,375,341; U.S. 9,035,341) are different patents and are not attributed here, and JP 6,367,659 B2 is reported literally as found even though it appears mis-mapped.

If you can supply (or authorize me to pull) the examiner's full "References Cited" sheet and the full texts of US 2017/0261463 A1 and the two Bosch publications, I can tighten the § 102 conclusions on those three and produce a claim-by-claim anticipation chart.

I'll pull details on the key prior-art references listed in the patent's own prior-art section so the obviousness analysis rests on what those references actually disclose, not just their titles.

Obviousness Analysis — U.S. Patent No. 10,775,341 (35 U.S.C. § 103)

Building on the earlier sections: the claim-summary section established that the narrowing limitation added in prosecution is the "an entirety of each of the one or more slits being formed directly between one of the plurality of oxygen-ion conductive solid electrolyte layers and a portion of the spacer layer in a stacking direction" language of claim 1, and the litigation section found no litigation or PTAB activity, which means there is no objective evidence of secondary considerations available to the patentee. Both points drive the analysis below.

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1. Framework and critical date

• Governing statute: AIA § 103 (application filed 2017‑03‑10; priority JP 2016‑061366, 2016‑03‑25). Prior art under § 102(a)(1) is anything publicly available before 2016‑03‑25; § 102(a)(2) art includes U.S. patents/applications with an effective filing date before that date.
• Presumption of validity: 35 U.S.C. § 282. Because essentially all of the principal references discussed below were cited by or considered by the examiner (they appear in the "Referenced Cited" list of the printed patent — see https://patents.justia.com/patent/10775341#3), a § 103 challenger bears the added burden of explaining why the combination was not, and would not have been, made.
• Rationale categories to apply (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007)): (i) combining prior-art elements according to known methods to yield predictable results; (ii) substituting one known element for another to obtain a predictable result; (iii) use of a known technique to improve a similar device in the same way; (iv) applying a known technique to a known device ready for improvement to yield a predictable result; (v) "obvious to try" where design incentives exist. Also relevant: Graham factors, and the "reasonably pertinent to the particular problem" analogous-art test (In re Klein, In re Bigio).

Claim 1 limitation map (the elements that must be accounted for)

Claim 5 is a method claim expressly tied to "the sensor element of claim 1," so it inherits 1.1–1.6 and adds a graduated-thickness disappearing-layer process. Claim 7 is an incorporation claim.

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2. The prior art of record — what each reference actually supplies

Group A — the layered NOx sensor architecture (supplies 1.1, 1.3–1.5)

A1. US 5,672,811 A — Kato et al., NGK Insulators (1997) (https://patents.google.com/patent/US5672811)
The admitted foundational reference. Discloses a first internal space fed through a first diffusion resistance, a first (main) oxygen pumping cell, a second internal space fed through a second diffusion resistance, a catalyst that reduces/decomposes NO, a second pumping cell that pumps out the oxygen liberated by decomposition, a reference-gas chamber with a reference electrode, and a heater that heats the two internal spaces to different temperatures (claim 38: heater "located nearer to the second internal space… so that the second internal space is heated to a higher temperature than the first internal space"). Claim 17 describes "a narrow, flat space having a predetermined diffusion resistance, which space has an opening exposed to said external measurement-gas space" — i.e., the slit-like entrance geometry itself.

Critically for motivation: the '811 family's background expressly identifies the clogging problem. The EP counterpart, EP 0 678 740 B1 (same 1994‑04‑21 priority; https://patentimages.storage.googleapis.com/d5/fa/25/fb286459415477/EP0678740B1.pdf) states that "if diffusion means or small leak formed in the pumping cell is clogged with oil ash in the exhaust gases, the pumping current may be undesirably changed, resulting in reduced measuring accuracy." This is an express, in-field articulation of the very problem the '341 patent sets out to solve — in a reference already of record. That is powerful § 103 motivation material.

A2. US 6,355,152 B1 — Kato & Nakagaki, NGK (2002) (https://portal.unifiedpatents.com/patents/patent/US-[6355152](/patent/6355152)-B1)
The closest structural ancestor of the claimed slit. The first diffusion rate-determining section is "formed with a slit having a laterally extending aperture formed at a front end portion of a second spacer layer to make contact with the lower surface of a second solid electrolyte layer… and a slit… formed at a front end portion of the second spacer layer to make contact with the upper surface of a first solid electrolyte layer." The two slits "have a substantially identical cross-sectional configuration, in which the length in the vertical direction [i.e., the stacking direction] is not more than 10 μm, and the length in the lateral direction is about 2 mm."
→ This reference squarely discloses two slits on opposite sides of a spacer-layer front-end portion, each formed directly between a solid electrolyte layer and a portion of the spacer layer, with the relevant dimension being a stacking-direction dimension (limitations 1.2 and, in substance, claim 3's "plurality of slits" and claim 4's two-slit configuration).
→ It also expressly teaches constant, identical slit width — which the patentee will argue is a teaching away from a width-transition slit.

A3. US 2005/0211554 A1 — Kurachi, NGK (2005) (https://patents.google.com/patent/US20050211554)
Discloses a laminar gas sensor element with first/second/third diffusion controlling passages in the form of slits, each defined between a partition wall "integrally fixed to the first solid electrolyte layer" and the second solid electrolyte layer, extending in the element width direction. It additionally discloses a "plugging-preventive space" in the distal end portion expressly to guard against plugging, and it is concerned with cracking of the first solid electrolyte layer caused by the unsupported/thermally stressed distal-end structure.
→ Supplies limitation 1.2 with an express in-field concern about plugging of the diffusion passage and about structural integrity of the thin distal-end layer (relevant to claim 5's sagging rationale).
(Japanese family member: JP 2005‑283266 A — https://patents.google.com/patent/JP2005283266A/en)

A4. JP 2011‑102797 A (PTL 2) and JP 3798412 B (PTL 1) — cited in the '341 patent itself as the conventional-art gas sensors with laminated elements. I could not retrieve verified full text for either; my characterization rests on their titles and on the NGK family literature (e.g., US 2011/0147214 A1, "Gas sensor and method for manufacturing sensor element," NGK, https://eureka.patsnap.com/patent-US20110147214A1, which describes laminating green sheets — the same process the '341 patent concedes — and an internal-space thickness of 50–180 μm). Flagged as unverified.

A5. Routine NGK background art (US 2009/0242404, US 2011/0233060, US 2011/0174049, US 8,246,800): protective/alumina layers over the outer pump electrode, green-sheet lamination, inspection of electrical characteristics. These supply no missing limitation but confirm that every ancillary feature of claim 1 was routine.

Group B — variable / tapered gas-passage geometry (targets limitation 1.6)

B1. US 2008/0282773 A1 / US 7,841,227 B2 — Varesi (Membranotec), published 2008 (https://patents.google.com/patent/US20080282773; https://patents.google.com/patent/[US7841227B2](/patent/US7841227B2)/en)
This is the most on-point disclosure of a tapered gas passage in the record, and it is cited on the face of the patent. It discloses "a capillary apparatus with capillaries which taper from one side… towards the other side… at least in sections," where "the cross-sectional area of each capillary increases from the first side to the second side." It further teaches the functional consequence of the taper:

"a particle entering the capillary 120 from the first side 14 is very likely to leave on the second side 16…" whereas particles entering from the narrow side are "very likely to leave the capillary apparatus again on the same… side."
It also discloses a "symmetrical capillary" that "tapers from both sides in the same manner up to a minimum diameter."
→ This is a gas passage whose width is larger at one end than the other, with a stated directional-transport effect. Its stated purpose (Knudsen-type separation/detection, gas enrichment) is not gas sensing. Non-analogous-art is the patentee's best defense here.

B2. US 2007/0108049 A1 — Wahl, Robert Bosch (published 2007) (https://patents.google.com/patent/US20070108049)
Same field of endeavor (layered ceramic exhaust-gas sensor element). Discloses a diffusion barrier with a gas-entry opening, and expressly teaches that the entrance-side geometry controls the diffusion resistance: "Diameter d1 of the gas entry opening, inside diameter d2 of the diffusion barrier… satisfy the condition d4 < d1 < d3," and that diffusion resistance can be trimmed by ablating the barrier through the (larger) entry opening. It also expressly offers a "linear geometry" alternative in which "the gas entry opening is introduced, for example, as a gap into the first solid electrolyte film, the width of the gap corresponding to the width of the diffusion barrier" — i.e., a slit-type entrance in a stacked solid-electrolyte sensor element.
→ Wahl supplies: (a) the concept that the entrance cross-section of a layered-sensor gas passage is a design variable that governs flow; (b) a slit-type ("gap") entrance; and (c) the express design notion of making the barrier initially undersized and opening it up — i.e., deliberately non-uniform entrance geometry.

B3. US 2003/0172741 A1 — Busch, "Sampling system for exhaust gas sensors" (2003) — cited of record; a sampling/flow-handling reference. I did not retrieve full text. Likely relevant only tangentially (as evidence that shaping/conditioning the sample-gas path ahead of a sensor was known). Flagged as unverified.

Group C — manufacture (targets claims 5–6)

• The '341 patent concedes that the green-sheet/pattern-print/laminating/pressure-bonding/firing process is conventional, and US 2011/0147214 (NGK) and US 2005/0211554 confirm laminating green sheets into a sensor element body. The use of burn-out ("disappearing"/"vanishing") material — theobromine, carbon, resin — to create an internal void or passage upon firing is likewise long-standing ceramic-sensor practice; the '341 patent itself gives theobromine as merely an example ("the material is not particularly limited thereto… it is only necessary that the material should burn and disappear during firing").
• US 2013/0255352 A1 (Ohtsubo, NGK) and US 2011/0174049 A1 (Shindo, NGK) are of record for sensor-element manufacturing/inspection. I could not verify Ohtsubo's disclosure of graduated-thickness burn-out layers — flagged.

Group D — closely-related earlier NGK/Denso filings not listed as "References Cited" but appearing in the record's family/citation data

• EP 2 927 676 A1 / US 10,215,725 B2 / JP 6498985 B2 (NGK, priority 2014‑03‑31), "Sensor element and gas sensor." The EP publication date is 2015‑10‑07, i.e., before the '341 critical date — potentially § 102(a)(1) art, and in any event analogous § 103 art from the same assignee and the same product family. Its content is not verified here; it should be the first thing a challenger pulls, because it is the closest-in-time same-assignee work.
• US 2017/0261463 A1 (Sugiura, Denso, effective JP filing 2014‑09‑16), "Gas sensor." Published after the critical date, so at most § 102(a)(2) art as to subject matter supported by its 2014 priority. Unverified.

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3. Grounds of rejection

Ground A — Claim 1 over Kato '152 (US 6,355,152) in view of Varesi (US 2008/0282773)

Where each limitation is met. Kato '152 supplies 1.1 (stacked solid-electrolyte layers + spacer), 1.2 (two slits each formed between a spacer-layer front-end portion and a solid electrolyte layer, whose controlling dimension is the stacking-direction "length in the vertical direction"), 1.3–1.5 (pump cell, measurement cell, heater — all standard in that family). Varesi supplies 1.6 by disclosing a gas capillary "tapered in at least one section" whose cross-sectional area increases from one side to the other.

Motivation / rationales.

1. Same problem, same field of gas transport through a micro-passage. Both Kato '152 and Varesi are directed to controlling the flow of a gas through a very small passage; Varesi expressly teaches the directionality the taper produces (particles entering the wide end traverse; particles entering the narrow end are blocked). A POSITA seeking to keep a diffusion-control slit from being occluded at its mouth would read Varesi as teaching "aperture larger at the gas-entry end."
2. KSR rationale (iv): applying a known technique to a known device ready for improvement. The diffusion-control slit is a known device; the field already recognized the oil-ash/soot plugging problem (US 5,672,811 family background, quoted above; the "plugging-preventive space" of US 2005/0211554). Widening the mouth of the slit is a predictable, mechanical modification.
3. Reasonable expectation of success. Both references treat a slit/capillary as a diffusion-resistance element; the diffusion resistance is a monotonic function of the passage cross-section, so a POSITA would expect a wider mouth to reduce the incidence of mouth occlusion and would expect to compensate the resulting resistance change by the exit-side dimension — which is exactly the claimed geometry (wide entrance, narrow exit, so total diffusion resistance is still set by the narrow exit).

Weakness of this ground. Varesi is arguably non-analogous (different field of endeavor; a separation/detection capillary, not a solid-electrolyte electrochemical cell), and it was cited of record and overcome — the examiner allowed over it. A challenger must therefore argue that Varesi's taper, combined with Kato '152's slit and the field's expressed plugging concern, makes the result "more than the predictable use of prior art elements according to their established functions" (KSR). That is a genuine argument, not a foregone conclusion, because Varesi's taper is for gas-species separation, whereas the '341 taper is for contaminant pass-through with downstream burn-off — a different exploitation of the geometry.

Ground B — Claim 1 over Kurachi (US 2005/0211554) in view of Wahl (US 2007/0108049), optionally with Varesi

Rationale. Kurachi supplies 1.1, 1.2 (slit between a partition wall integrated with a solid electrolyte layer and the facing solid electrolyte layer) and 1.3–1.5, plus the express distal-end plugging concern. Wahl is the same field (Bosch layered sensor element), and supplies the teaching that the entrance-side aperture dimension governs the diffusion resistance and can be deliberately made non-uniform, including a "linear geometry" in which the entry is a gap into the solid electrolyte film.
Motivation: Wahl's "diffusion barrier is configured in such a way that… the diffusion flow prior to material ablation is less than the target value… so that the diffusion distance is decreased by the material ablation and the diffusion flow can thus be increased" shows a POSITA consciously using entrance geometry as a design lever in the same device class. Combining Kurachi's plugging-resistant slit with Wahl's teaching that the entrance cross-section is a free design variable yields claim 1 with a predictable result.
Weakness: Wahl accomplishes its non-uniformity by laser ablation of a sintered part, not by molding a tapered slit; and Wahl does not address soot burn-off.

Ground C — Claim 1 over the patent's admitted prior art (FIG. 10 / PTL 1 / PTL 2) in view of Varesi and/or Wahl

The '341 specification itself describes the FIG. 10 conventional sensor (gas introduction portion 310 as a slit-shaped entrance, internal spaces, measurement electrode, outer pump electrode, reference electrode/space, heater) and states the problem: solids "adhere to an entrance of the slit-shaped gas introduction portion 310," entrance temperature "about 400° C. to 600° C." is too low, and the introduced gas amount falls. This is the patentee's own admission of the prior-art base and of the problem. Once the problem is conceded and the base is admitted, the only remaining question is whether tapering the slit mouth was obvious. Ground C therefore reduces to Grounds A/B on the last limitation, and the admission strengthens the challenger's motivation showing.

Ground D — Claims 3 and 4

• Claim 3 ("a plurality of slits") is directly met by Kato '152 (two slits) and by Kurachi (three slit-shaped diffusion controlling passages). This claim adds essentially nothing over claim 1 and would fall with it.
• Claim 4 (two slits on opposite sides of a layer portion, at least the one on the heater side being the width transition slit) is met by Kato '152's two slits on opposite sides of the spacer front-end portion, combined with the well-known NGK heater placement (US 5,672,811's heater between substrate layers, located nearer the internal spaces; the '341 patent itself places heater 72 between the second and third substrate layers). Placing the width-transition geometry on the heater-proximal side is a predictable design choice in light of the recognized physics (higher temperature → faster burn-off), and is at most a routine optimization. The '341 specification's own rationale ("since the width transition slit is provided on the side close to the heater, the inside… is easily heated to a high temperature") states the expected, not an unexpected, result.

Ground E — Claims 5 and 6 (method)

Claim 5: Given that claim 1 is obvious, the method of making a slit of that shape by (a) preparing green sheets, (b) printing disappearing-material layers of graduated thickness, and (c) laminating and firing is the predictable application of a known fabrication technique to a known structure. Reference support for the technique: the '341 patent concedes both the green-sheet process and the burn-out-layer concept (theobromine "for example"; "the material is not particularly limited thereto"); US 2005/0211554 and US 2011/0147214 confirm lamination/burn-out practice in this exact device class.
Best patentee argument for claim 5: no reference of record is verified to disclose a burn-out layer whose thickness increases toward the entrance. If unverified/absent, that is a factual gap a challenger must fill (e.g., with a primary reference teaching variable-thickness burn-out or with a declaration of what a POSITA would do). I did not verify a reference teaching graduated-thickness burn-out layers — flag this as the principal evidentiary gap.
Claim 6 (two-step print: a first layer at least as long as the slit-forming portion, then a shorter second layer) is routine optimization by a known printing method — screen-printing successive layers of different lengths is elementary; the '341 specification itself says only that they "can be easily formed, for example, by printing." No separate motivation is needed.

Ground F — Claim 7

Claim 7 is purely an incorporation claim ("A gas sensor including the sensor element according to claim 1"). It rises and falls with claim 1 and adds no independent element.

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4. Non-obviousness arguments the patentee will press (and an assessment)

1. Teaching away / uniform-width teaching in Kato '152. Kato '152 goes out of its way to require the two slits to have "a substantially identical cross-sectional configuration" and an "identical aperture width" up to the first chamber. A patentee will argue this teaches uniformity away from the claimed taper. Assessment (moderate): a court would likely find this a disclosure of an embodiment selected to damp exhaust-gas pulsation, not a criticism of, or disincentive to, tapered geometry. The Federal Circuit generally requires that a teaching-away reference "criticize, discredit, or otherwise discourage" the claimed subject matter. That standard is probably not met — but it is the patentee's strongest single argument and it creates a genuine fact question.

2. Non-analogous art (Varesi). Varesi is a detector/enrichment capillary device premised on mean-free-path effects, not an electrochemical sensor element. Assessment: a challenger will respond with the "reasonably pertinent to the particular problem" test — Varesi is pertinent to the problem of gas flow through a small passage, even if not to NOx sensing. Still, this is a real vulnerability for the challenger, and Varesi's taper is exploited for separation, not anti-fouling, which weakens the "same problem" linkage.

3. Claim 2's dumbbell mouth. Claim 2 requires that the entrance-side slit width be larger in the entrance end portions than in the entrance center portion, with at least the end portions wider than the exit. I located no reference of record, and no reference outside the record, that discloses this "dog-bone" mouth geometry. If a defendant/re-examiner cannot supply art for it, claim 2 is the claim most likely to survive a § 103 challenge, and it should be treated as the commercially meaningful fallback. Assessment: this is the strongest non-obviousness position in the patent.

4. Claim 1's "entirety… directly between one solid electrolyte layer and a portion of the spacer layer." The prosecution-added language was plainly intended to distinguish references in which the gas entry is an opening through a solid-electrolyte film (Wahl's cylindrical gas-entry opening / gap) or a capillary in a separate capillary apparatus (Varesi). Assessment: this limitation is met by Kato '152 and Kurachi, whose slits are literally at the spacer/solid-electrolyte interface, so the limitation does not save claim 1. It does, however, defeat any § 102 anticipation built on Wahl or Varesi alone.

5. The "sagging" benefit (claim 5). The specification argues the graduated-thickness burn-out layer prevents the unsupported entrance-side green-sheet portion (105a) from hanging down during firing and closing the slit. A patentee may offer this as evidence of an unexpected mechanical benefit. Assessment: the sagging problem is a known firing-shrinkage issue; the reference (thicker burn-out = more support before burnout, more clearance after) is a predictable mechanical consequence, and there is no evidence in the record of unexpected results (no data, no comparative examples reported in the specification).

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5. Secondary considerations

• The earlier litigation section found no district-court, CAFC, ITC, or PTAB activity involving 10,775,341 in the sources searched. There is therefore no litigation-induced objective evidence (no nexus evidence of commercial success, copying, industry praise, or failure of others) in the public record to weigh against the prima facie case.
• The claims are narrow and incremental (a mouth-geometry change to a known diffusion-control slit in a known laminated NOx sensor). Where objective evidence is absent, KSR's "predictable results" and "design incentive" rationales are at their strongest.

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6. Bottom line

Overall: Claim 1 presents a legitimate but not overwhelming § 103 case. The record contains a tapered gas passage (Varesi), the exact spacer-interface slit architecture (Kato '152; Kurachi), and — unusually helpfully — an in-field, of-record articulation of the soot/oil-ash clogging problem (US 5,672,811/EP 0 678 740 background). Against that is the fact that the two best secondary references (Wahl and Varesi) are on the face of the patent and were overcome, and Kato '152 arguably points to uniform slit width. The realistic posture is: claim 1 is vulnerable to a well-constructed § 103 challenge; claim 2 is the likely redoubt.

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7. Confidence, and what must be verified

Confidence: moderate.

• I retrieved and read substantial text for US 5,672,811 (and its EP 0 678 740 family), US 6,355,152, US 2005/0211554, US 2007/0108049, US 2008/0282773/US 7,841,227, and US 2011/0147214. Characterizations of these are grounded in quoted text.
• Not verified / based only on titles, abstracts or family data: JP 3798412 B (PTL 1), JP 2011‑102797 A (PTL 2), US 2013/0255352 A1 (Ohtsubo), US 2009/0242404, US 2011/0233060, US 2011/0174049, US 8,246,800, US 2003/0172741 (Busch). I could not retrieve full text and did not find a reference disclosing graduated-thickness burn-out layers or the claim‑2 dumbbell mouth.
• Should be pulled first by anyone actually building this case: JP 6498985 B2 / EP 2 927 676 A1 / US 10,215,725 B2 (NGK, priority 2014‑03‑31) — same assignee, same product family, EP published 2015‑10‑07 (before the critical date) — and US 2017/0261463 A1 (Denso, effective filing 2014‑09‑16) as potential § 102(a)(2) art. Their content is unverified here and they are not listed in the patent's "References Cited," so they would not be burdened by the § 282 "considered by the examiner" problem.
• Section 102 check to run in parallel: whether Kato '152 or Kurachi anticipate any dependent claim outright, and whether the graduated-burn-out-layer method of claim 5 is anticipated by any NGK manufacturing-family publication from 2013–2015.
• Per the operating rules, the legal-status and family data above (e.g., "active, expires 2037‑12‑31") are aggregator assumptions, not legal conclusions, and any definitive litigation/PTAB negative would need to be confirmed against PACER, USPTO Patent Center, and the PTAB docket.