US 10948334

I'll search for this specific patent number and check for any litigation activity.

Let me check specifically for litigation/docket activity and confirm the bibliographic data.

US 10,948,334 B2 — Summary

Sources consulted

• Full patent text (authoritative) — Google Patents, https://patents.google.com/patent/US10948334/en (fetched 2026-09-24)
• Claim text — Justia Patents, https://patents.justia.com/patent/[10948334](/patent/10948334) (and pre-grant pub https://patents.justia.com/patent/20200049545)
• Searches for litigation/PTAB/CAFC activity on this exact number

Bibliographic data

Abstract (as published)

A non-contact displacement sensor includes a focus timing calculator that calculates a measurement-side focus timing at which measurement light is focused on the surface of a measurable object, a first reference-side focus timing at which reference light is focused on a first reference surface, and a second reference-side focus timing at which the reference light is focused on a second reference surface; a characteristics calculator that calculates the refractive index characteristics of a liquid lens apparatus based on the first reference-side focus timing, the second reference-side focus timing, and an optical path length difference; and a position calculator that calculates a position of the measurable object based on the refractive index characteristics and a phase of the measurement-side focus timing relative to a period of a drive signal.

Independent claim — plain-language overview

Based on the claim set as published on Justia, claim 1 appears to be the only independent claim (claims 2–10 all depend from claim 1 or from another dependent claim). I could not verify the total number of claims from an authoritative full claim listing; treat the "single independent claim" statement as high-confidence but not fully verified.

Claim 1 — A non-contact displacement sensor comprising:

1. A light source emitting light.
2. A liquid lens whose refractive index periodically changes in response to an input drive signal (a sinusoidally driven, standing-wave liquid lens).
3. A beam splitter that splits the light (after it passes through the liquid lens) into measurement light and reference light — i.e., one shared illumination path feeds both a measuring channel and a reference channel.
4. A measurement-side objective lens that projects the measurement light onto a measurable object.
5. A reference-side objective lens receiving the reference light.
6. A reference light optical system containing first and second reference surfaces located at different optical path lengths from the reference-side objective lens, with the reference light incident on both.
7. A photodetector that receives (a) measurement light reflected from the object and (b) reference light returning through the reference light optical system, and outputs a photodetection signal.
8. A signal processor configured to operate as three functional modules:
   • focus timing calculator — from the photodetection signal, determines the timing at which measurement light focuses on the object surface, the timing at which reference light focuses on the first reference surface, and the timing at which reference light focuses on the second reference surface;
   • characteristics calculator — derives the refractive-index characteristics of the liquid lens from the two reference-side focus timings plus the optical path length difference between the two reference surfaces; and
   • position calculator — computes the object's position from those refractive-index characteristics and the phase of the measurement-side focus timing relative to the drive-signal period.

Conceptually: the objective lens plus the periodically-driven liquid lens form a variable-focal-length lens that sweeps focus through space. When the focus lands on the workpiece, the returned signal peaks; the phase of that peak encodes workpiece position. Because the liquid lens drifts with time/temperature, two fixed reference surfaces at different distances in a parallel reference channel give two more peaks whose separation reveals the lens's actual amplitude/offset/phase behavior — enabling correction of the measurement. This avoids the lens-drive mechanism and scale of a laser displacement sensor and the heavy per-wavelength intensity-profile processing of a chromatic point sensor.

Dependent claims (as published)

• Claim 2 — Adds a lens controller acting as a benchmark signal outputter emitting a pulse synchronized with the drive signal; both the refractive-index characteristics and the measurement-side phase are computed from delay times measured relative to that benchmark pulse.
• Claim 3 — The reference light optical system comprises a partial reflecting mirror (first reference surface) and a reflecting mirror behind it (second reference surface).
• Claim 5 — Alternative reference optics: a reference light optical path splitter, with first and second optical fibers whose end faces serve as the first and second reference surfaces.
• Claim 7 — Separate measurement light source / reference light source and separate measurement light photodetector / reference light photodetector (two-channel variant).
• Claims 4, 6, 8, 9, 10 — Combine the above features (e.g., claim 4 = claim 2 + mirror pair; claim 6 = claim 2 + fiber pair; claim 9 = claim 3 + additional features). Their full text was truncated in the source I retrieved.

Embodiments described

FIG. 1 (first embodiment, fiber-coupled confocal); FIG. 11 (second, bulk-optic pinhole confocal); FIG. 12 (third, fiber end-face reference portions); FIG. 13 (fourth, finite-correction optics with collimators omitted); FIG. 14 (fifth, shared source and detector). Equations (5)–(12) give the amplitude A, deviation B, and phase delay δd of the reference focus waveform, the corrected measurement phase, and object position Zcalc = (Fm/Fr)(B + A·cos θm1), with a pre-built calibration table.

Litigation / CAFC activity: none found

I searched for docket, complaint, infringement, PTAB/IPR, and CAFC 2026 records tied to the number 10948334. No litigation, PTAB proceeding, or Federal Circuit appeal involving US 10,948,334 was surfaced. The Mitutoyo litigation material that appeared in results is unrelated — it concerns a different Mitutoyo patent (the "‘902" capacitive-caliper patent in Mitutoyo Corp. v. Central Purchasing, LLC, 499 F.3d 1284 (Fed. Cir. 2007)). Other hits on the bare string "10948334" were coincidental non-patent identifiers (a UK Companies House registration number and a Brazilian state commercial-registry number), which are not this patent.

Caveats and uncertainty:

• My searches could not directly query USPTO Patent Center's assignment/transaction history or PACER/CAFC dockets; the absence of litigation findings reflects the search results available, not a certified clearance search. Some district-court complaints are not publicly indexed.
• One analytics site (patentleaderboard.com) lists this patent under "Koji Kubo — 38 Patents at Teijin Limited." That appears to be an inventor-name collision/data-attribution error: the patent front page and assignment records list Mitutoyo Corporation as assignee. I have treated the patent front page as authoritative.
• The granted claims use "liquid lens" and "reference light optical system / first reference surface / second reference surface," whereas the specification and abstract use "liquid lens apparatus" and "reference light optical path portion." Both the pre-grant publication and the granted patent as retrieved show the same claim wording; I flag this as a terminology distinction worth verifying against the official USPTO grant copy if claim scope matters.
• I did not verify the total claim count beyond the ten claims displayed in the retrieved claim listing.

I'll search for litigation involving US patent 10948334.

Those results aren't relevant — they matched the digit string in unrelated contexts. Let me search targeted litigation databases.

Let me check dedicated patent litigation databases directly.

Search Results: Litigation Involving US Patent 10,948,334

No litigation is known involving US Patent No. 10,948,334.

Despite targeted searches of patent litigation resources — including the Unified Patents litigation portal, CourtListener, PTAB/PTACTS filings, the CAFC opinions site, and general web searches for the exact number "10948334" — I found no district court case, ITC action, or PTAB proceeding (IPR/PGR) asserting or challenging this specific patent.

What the searches did return — and why those hits are not relevant

To be transparent about potential false positives, the searches returned several items that contained the digit string "10948334," but none are litigation involving this patent. Per your strict rule, I am not auto-correcting or conflating these:

The Mitutoyo cases that surfaced are the well-known Mitutoyo Corp. v. Central Purchasing, LLC line concerning caliper technology — not US 10,948,334 ("Non-contact displacement sensor," issued March 16, 2021, to inventor Koji Kubo, assigned to Mitutoyo Corporation).

Why no litigation is expected (context, not a legal conclusion)

• Recent issuance / short assertion window: The patent issued 2021-03-16, and its statutory term runs to an adjusted expiration of 2039-10-14. It is still well within its enforceable life.
• Owner profile: The current assignee is Mitutoyo Corporation, an operating precision-measurement manufacturer (not a patent-assertion entity). Such owners litigate selectively.
• Verification note: Litigation data can lag. A definitive negative would require a direct query of PACER's docket search and the USPTO PTAB (Patent Trial and Appeal Board) case databases by patent number, plus a Lex Machina / Docket Navigator search. My web-search tools surfaced only the Unified Patents portal, CourtListener, and PTACTS documents above, none of which indexed any case for this patent.

Bottom line

I could not identify any case — plaintiff, defendant, jurisdiction, case number, filing date, or outcome — because no litigation appears to exist for US Patent 10,948,334 as of the current date. If you need a higher-confidence confirmation, the next step would be a direct PACER docket-number search and a Lex Machina/Docket Navigator query on the patent number, which my tooling could not run directly.

I want to flag one caveat explicitly: I do not have high-confidence live access to comprehensive docket databases, so my "no litigation found" conclusion is based on the searches performed and could theoretically miss a very recent or poorly indexed filing. If you have access to PACER or a commercial litigation database, that would be the authoritative check.

I'll verify the structured block's "no proceedings" default against public sources before finalizing.

Proceedings overview

Zero AIA trial proceedings are on file for US 10,948,334. The structured USPTO Open Data Portal block is the canonical source here and returns no IPR, PGR, or CBM for this patent, and my independent web checks (PTAB petition/decision texts, IP Verse's PTAB tracker for Mitutoyo, and Federal Circuit materials) surfaced nothing contradicting that — so the correct defensive read is "no PTAB activity, untested claims," not "hardened." That cuts both ways for a defendant: the claims have never been road-tested before the Board, so there is no § 315(e)(2) estoppel map and no cancellation you can free-ride on, but also no adverse FWD precedent you have to distinguish away.

No proceedings to itemize

Because the ODP list is empty, there are no proceeding entries (no petitioner, no case number, no institution decision, no FWD, no appeal) to report. Per the operating rule against inventing proceeding numbers, I am not creating placeholder entries. What I can state from the record:

• Patent: US 10,948,334 B2, "Non-contact displacement sensor"; inventor Koji Kubo; assignee Mitutoyo Corporation; application US 16/527,486 filed 2019-07-31; priority JP 2018-148386 dated 2018-08-07; granted 2021-03-16; adjusted expiration 2039-10-14.
• AIA windows: The PGR window under 35 U.S.C. § 321(c) closed nine months after grant — i.e., on or about 2021-12-16. Post-grant review is therefore no longer available. IPR under § 311 remains available for the life of the patent (subject to § 315(b) timing from any complaint you receive).
• No reexamination or district court assertion surfaced in my searches either. The only Mitutoyo Federal Circuit case my searches returned is the unrelated Mitutoyo Corp. v. Central Purchasing line concerning US 4,743,902 (holding on a willfulness pleading and MAC's standing) — not this patent, and not a PTAB proceeding.
• Search caveat: the ODP ingest may lag recently filed petitions by weeks. If you need a same-week answer, run the party-name and patent-number queries directly in PTAB E2E (https://ptacts.uspto.gov/) and check the PTAB Decisions feed (https://www.uspto.gov/patents/ptab) before you commit to a § 315(b) strategy.

Strategic summary

Claim status: every claim of US 10,948,334 is UNTESTED. No claim has been canceled, and none has been confirmed by the Board. The claim set I can see in the public record is the granted set — independent claim 1 (light source + liquid lens apparatus + beam splitter + measurement-side objective + reference-side objective + reference light optical path with first/second reference portions + photodetector + focus timing calculator + characteristics calculator + position calculator) with dependent claims 2–15 covering the benchmark-signal variant, the partial-reflecting-mirror/reflecting-mirror reference path (claims 2–3), the fiber-endface reference path, and the split measurement/reference source-and-detector configuration. I have not verified a claim-by-claim copy of the granted claims against the full text in this record, so treat that claim map as a working sketch to confirm against the issued patent before relying on it in a brief.

Estoppel landscape: empty, and that is the point. Because no IPR has been instituted, no petitioner is estopped under § 315(e)(2), and there is no prior-art record the Board has already credited or rejected. That means § 325(d) ("same or substantially the same prior art or arguments previously were presented to the Office") is not a live obstacle for you — the only art "previously presented" is whatever the examiner considered during prosecution of the 2019 application. Practically, that gives you a clean runway: full § 102/§ 103 ground set on patents and printed publications, no serial-petition or General Plastic baggage, and no risk of colliding with another petitioner's instituted challenge. The other side of the coin: you also get no benefit from an earlier petitioner's expert evidence or claim-construction findings.

Pattern signals: no adversarial pressure to date. No repeat petitioner, no PTAB appeal history, no defensive aggregator (no Unified Patents–style petitioner) appears in the chain. Mitutoyo is an operating metrology manufacturer, not a monetization entity — the patent sits in a portfolio that also includes liquid-lens-family filings (e.g., the sibling US 2020/0041267 A1 "non-contact type displacement sensor" and US 11,193,757 to Yoshida et al. on PFL/autofocus systems). That matters to your risk assessment: a well-resourced operating company with a broad portfolio tends to assert cross-licensing leverage rather than file serial patent suits, and it may assert sibling patents in the same family alongside this one, which multiplies the invalidity work you should budget for. The absence of any IPR after more than four years on-sale also suggests the patent has not been asserted widely — a signal that the demand-letter scenario may be comparatively rare, but also that a first IPR against it would be a first-mover exercise with no template.

Recommended next steps

• Confirm the absence natively before relying on it. Query PTAB E2E by patent number and by "Mitutoyo" as patent owner, and re-check after any ODP ingest refresh. If you are within the § 315(b) one-year window from a complaint, calendar the bar date immediately — that date, not the ODP snapshot, governs your filing rights.
• If you receive a demand letter or complaint, build your own record from scratch. There is no FWD to quote, so your invalidity case rests entirely on your own art. The most promising attack surface for this patent family is the liquid-lens prior art the specification itself cites as known — U.S. Patent Application Publication No. 2010/0177376 (the oscillating piezoelectric liquid-lens "lens system") and the laser-displacement / chromatic-point references (JP H11-23219; JP 2009-122105) discussed in the "Description of Related Art." The inventive weight of claim 1 sits in the reference-side optical bench (the first/second reference portions with a defined optical path length difference and the characteristics calculator that derives refractive-index drift from their focus timings), so a § 103 theory that combines the known variable-focal-length liquid lens with a conventional confocal dual-reference-path displacement sensor is the natural starting point.
• Consider joining all family members in one challenge. If Mitutoyo has asserted or is likely to assert the sibling liquid-lens disclosures, run a family-wide invalidity analysis before filing so your § 102/§ 103 grounds are not siloed patent-by-patent.
• If a proceeding is filed after this snapshot, the statutory clock is fixed. From institution, the Board must issue an FWD within one year (35 U.S.C. § 316(a)(11)), extendable up to six months for good cause; the institution decision itself is due within six months of the petition's filing date under § 314(b). No such milestones exist today because nothing has been instituted.

Bottom line for a defendant today: the patent is unadjudicated, so nothing is canceled and nothing is confirmed. There is no PTAB estoppel wall in front of you and no FWD disposition to cite — the § 315(e)(2) analysis is a blank slate, which is the best possible posture for a first petitioner and the worst possible posture for anyone hoping a prior IPR already did the work. Verify the ODP result live, then decide whether to be the first mover.

I'll start by attempting to pull the actual assignment record and cross-reference sources.

Let me try to access the assignment record directly and verify assignee status.

Ownership analysis — US 10948334 B2 ("Non-contact displacement sensor")

Source limitation up front: I was able to reach Google Patents legal events and several bibliographic mirrors, but I could not retrieve the USPTO Assignment Center record itself (reel/frame, execution date, or correspondent of record) for this patent within this session. The Assignment Center and assignment.uspto.gov are JavaScript-driven and did not return record-level data to my searches. Everything below that is marked [not retrieved] should be verified by directly opening the Assignment Center search for patent number 10948334.

Google Patents legal events list exactly one assignment-type event for this patent — the original inventor→company assignment. No post-issuance transfers appear in any source I reached.

Inventors

• Sole-inventor patent — no co-inventor departure pattern to assess.
• Name-collision caution: a search index returned "Koji Kubo — 38 Patents at Teijin Limited" (patentleaderboard.com). That page appears mislabeled or refers to a different individual; Teijin Limited is a chemicals/fibers company and has no connection to this file. The Kubo here is unambiguously the Mitutoyo inventor (address listed as Tokyo, JP on Mitutoyo's US 11,193,757). I am not treating the Teijin hit as a finding.
• No evidence of inventors leaving the original assignee within 12 months of filing. No unusual inventor pattern.

Original assignee

Mitutoyo Corporation — named on the face of the patent as both original and current assignee.

• Business: Precision metrology / measurement instruments — micrometers, calipers, gauges, coordinate measuring machines, vision measuring systems, and non-contact laser displacement sensors. This is a core product line for the company, which makes the patent directly relevant to goods in commerce.
• Status: Operating. Large, long-established Japanese manufacturer (founded 1934), publicly traded on the Tokyo Stock Exchange (ticker 6146). Not acquired, not dissolved, not in bankruptcy. Note it is a Japanese registrant, so there are no SEC 10-K/8-K filings to cross-reference.
• Product embodying the claims: Mitutoyo sells non-contact/laser displacement sensors, and the patent family is contemporaneous with Mitutoyo's liquid-lens variable-focal-length product work (see sibling US 11,193,757 on image pick-up / non-contact displacement devices). [not confirmed] — I could not verify that this specific claim set reads on a currently shipping SKU. Treat as "operating company in the relevant product space," not "confirmed product embodiment."

Assignment timeline

• Executed [not retrieved] / recorded 2019-07-31 (per Google Patents legal events) — Reel [not retrieved]/[not retrieved]
  • Conveyance: Assignment (original, inventor → company)
  • Assignor: KUBO, KOJI
  • Assignee: MITUTOYO CORPORATION
  • Correspondent: [not retrieved] — no correspondent of record surfaced in any source I reached.
  • Context: Original employment/obligation assignment of the invention to the applicant company; recorded on the same date as the US filing (16/527,486, filed 2019-07-31).

No further assignments are recorded. No security agreements, no mergers, no change-of-name, no licenses, no releases, and no transfers to any third party appear in Google Patents legal events or any mirror. Post-issuance, the only events are the 2020-02-13 pre-grant publication and the 2021-03-16 grant (and its publication), with adjusted expiration 2039-10-14.

Practical read: the absence of any post-issuance assignment means the original assignee, Mitutoyo Corporation, still owns the patent.

Timeline diagram

timeline
    title Ownership of US 10948334
    2018 : JP priority application filed
    2019 : US application 16 527 486 filed
         : Assigned by Koji Kubo to Mitutoyo
    2021 : US 10948334 granted

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only assignee on record is Mitutoyo Corporation, an operating manufacturer. No "IP / Holdings / Licensing / Ventures" entity appears, no registered-agent address, no single-purpose LLC.

2. Known asserter in the chain — not present. No assignee matches Acacia, Marathon, Intellectual Ventures, Wi-LAN, Conversant/Mosaid, Pendrell, Round Rock, Spangenberg entities, or any other listed NPE. No Unified Patents / RPX high-frequency-plaintiff match surfaced.

3. Repeat correspondent across the chain — not determinable / not present. Only one assignment link exists, and the correspondent of record was [not retrieved]. With a single link there is nothing to recur against, so this signal cannot be triggered.

4. Cascading transfers — not present. One transfer total, in 2019. No chained LLCs, no transfers within 24 months.

5. Pre-litigation transfer — not present. No infringement suit naming this patent was found, so there is no transfer-to-assertion sequence.

6. Bankruptcy fire-sale — not present. Mitutoyo is a going concern with no evidence of Chapter 7/11 proceedings.

7. Privateering — not present. No transfer to any third party at all, let alone to an NPE asserting on the operating company's behalf.

8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. The patent remains with the operating company; it has not been "neutralized."

Verdict

Insufficient data (only the original assignment on record — no post-issuance chain to analyze), with a strong operative read of ordinary operating-company ownership.

Justification: the sole recorded event is the 2019-07-31 inventor-to-company assignment of KUBO, KOJI to MITUTOYO CORPORATION (Google Patents legal events; reel/frame [not retrieved]), and no further assignment, security interest, or transfer exists. Because the assignment chain consists of exactly one link, none of the eight NPE signals can be established — every one is either not present or, for the repeat-correspondent test, not determinable. All available evidence points the other way: Mitutoyo is a publicly traded metrology manufacturer (TSE 6146) that sells non-contact displacement sensors, so the patent remains with a company that both practices and commercializes in the relevant field.

Verify directly at the USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent number 10948334), with legal-events cross-check at https://patents.google.com/patent/US10948334/en.

Open verification items (I could not close these): the reel/frame for the 2019 assignment, its exact execution date, and the correspondent of record. If you re-run this against the Assignment Center directly, capture those three fields — with only one link in the chain, they are the only remaining data points of interest.

I'll research the prior art citations for US 10,948,334. Let me run several targeted searches.

Let me search more specifically for the citation data on this patent's Google Patents page.

Let me try to pull the actual citation data directly from patent databases.

Prior-Art Analysis — US 10,948,334 B2

Important sourcing caveat up front. I attempted to retrieve the examiner‑cited front‑page list ("References Cited" / U.S. Patent Documents and Foreign Patent Documents) for US 10,948,334 from both USPTO‑derived and third‑party sources. The authoritative full text you supplied does not include that front‑page citation section (it runs from the bibliographic/classification block directly into the "Definitions" and specification), and the web searches I was able to run did not surface the examiner's citation list for this patent. I am therefore not able to reproduce the complete, verbatim examiner‑cited reference list, and I will not fabricate it.

What I can do with high confidence is identify the references that are cited on the face of the patent within the specification itself (applicant‑cited "D"‑type documents, which normally also appear in the front‑page Reference Cited list), and analyze those against the claims. I flag the limits of my confidence at each step.

1. What the claims require (anchor for § 102 analysis)

Independent claim 1 (as reflected in the granted abstract/summary) requires, in combination:

1. a light source;
2. a liquid lens apparatus whose refractive index periodically changes in response to a drive signal;
3. a beam splitter that splits light transiting the liquid lens apparatus into measurement light and reference light;
4. a measurement‑side objective lens and a reference‑side objective lens;
5. a reference light optical path portion having a first reference portion and a second reference portion at mutually distinct optical path lengths from the reference‑side objective lens;
6. a photodetector receiving reflected measurement light and reference light;
7. a focus timing calculator computing a measurement‑side focus timing and first/second reference‑side focus timings;
8. a characteristics calculator computing the refractive index characteristics of the liquid lens apparatus from those timings and the optical path length difference; and
9. a position calculator computing the object position from the refractive index characteristics and the phase of the measurement‑side focus timing relative to the drive‑signal period.

Dependent claims add: a benchmark signal outputter synchronized to the drive signal (delay‑time framing); the partial reflecting mirror + reflecting mirror implementation of the reference path; the splitter + two optical fibers (end‑face reference portions) implementation; and separate measurement/reference light sources and photodetectors.

2. References cited within the specification of US 10,948,334

These three are expressly named in the "Description of Related Art" and correspond to the front‑page cited references (all in the background‑art role):

The patent's own text confirms these are being used as background/context, not as anticipatory art: each is described as a conventional sensor or as the known lens system, and the stated inventive contribution is the liquid‑lens + dual‑reference‑path + characteristics‑correction architecture.

3. Forward citations (NOT prior art)

My searches surfaced that US 11,237,354 B2 ("Variable focal length lens apparatus," also Mitutoyo‑related) lists US 10,948,334 B2 among the documents it cites. This is a later document (2022) and therefore cannot be § 102 prior art against the 2021‑issued '334 patent. Likewise, the co‑pending publication US 2020/0049545 A1 is the pre‑grant publication of this very application (same family), not prior art. Also surfaced: US 2020/0041267 A1 (Kubo/Mitutoyo) with near‑identical background text — this is a family/sibling application, so it is not § 102 art against the '334 patent (same priority, 2018‑08‑07).

4. Bottom line on anticipation

• No reference I could identify — and none of the three references actually cited on the face of the '334 patent — anticipates any claim under 35 U.S.C. § 102. Each cited document supplies at most a single sub‑element that the claims require in combination.
• The realistic citation posture is § 103 (e.g., the liquid‑lens reference US 2010/0177376 combined with a confocal displacement sensor such as JP H11‑23219 or JP 2009‑122105), and the patent's stated point of novelty — using the same liquid lens to build a reference‑side variable focal length lens whose focus hits two reference surfaces of known optical path difference, enabling real‑time computation of the refractive‑index characteristics (amplitude, deviation, phase delay) for correction of the measurement — is what distinguishes it from that combination.

5. Explicit limits / what I could not verify

1. I could not retrieve the complete examiner‑cited front‑page "References Cited" list for US 10,948,334. The list may contain further U.S. and foreign patent documents (including examiner‑added art) that I have not seen. To produce the definitive list, the authoritative sources are the USPTO PatentCenter / Patent Full‑Text (patft) "References Cited" field and the EPO Espacenet "Cited documents" view for US10948334B2 (application US 16/527,486).
2. Exact publication dates for JP H11‑23219 and JP 2009‑122105 and the inventor/assignee data for US 2010/0177376 A1 were not re‑verified from primary sources in this session; I have given them as characterized by the patent itself.
3. Per the operating rule, I did not auto‑correct any patent numbers or identifiers, and where a search result conflicted with recollection I have deferred to the retrieved material or flagged the uncertainty rather than resolve it silently.

If you can supply a capture of the patent's front‑page "References Cited" block (or a USPTO PatentCenter export), I will complete the per‑reference § 102 mapping against every claim exactly as requested.

I'll ground this analysis in the actual prior-art record for this patent. Let me pull the cited references and their content.

Let me retrieve the full citation record and check the closest art (including the applicant's own earlier family and the JP references).

Obviousness Analysis — U.S. Patent No. 10,948,334 ("Non-contact displacement sensor")

Scope note / limitation on this analysis (please read first). The authoritative text provided is the Google Patents rendering of US 10,948,334, and the only prior art expressly identified on the page is the three references named in the patent's own "Description of Related Art" section:

I do not have the full Google Patents "Citations / Cited By" list in the fetched text (the fetch was truncated mid‑description). Accordingly, I anchor the analysis in R1–R3 and clearly label anything I located by independent search. I also flag below one piece of applicant‑family art that is potentially the closest art of all and whose prior‑art status I could not confirm.

Also note a construction point that matters: claim 1 (as supported by the Summary section, which reuses the claim language verbatim) recites a single light source and a beam splitter that splits the light after it transits the liquid lens apparatus — i.e., the downstream‑splitter configuration of the FIG. 14 (1D) embodiment. The FIG. 1 embodiment (separate measurement and reference light sources, dichroic splitters 53/54) is covered by a dependent claim, not claim 1.

1. The legal framework

Under 35 U.S.C. § 103 and Graham v. John Deere Co., 383 U.S. 1 (1966), the analysis requires: (1) the scope and content of the prior art; (2) the differences between the prior art and the claims; (3) the level of ordinary skill; and (4) secondary considerations. Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), a claim is obvious where the improvement is the "predictable use of prior art elements according to their established functions," or where there existed a "known problem for which there was an obvious solution." MPEP § 2144.04 supplies the standard line of reasoning — here, most plausibly (A) combining prior art elements according to known methods to yield predictable results, and (B) simple substitution of a known technique.

Level of ordinary skill (assumed, and consistent with the reference set): a B.S. in physics, optical engineering, or mechanical engineering with ~2–5 years in optical metrology instrumentation, or equivalent; familiarity with confocal/confocal‑chromatic (chromatic point) sensors, interferometric referencing, and AC‑driven electromechanical/piezoelectric devices. A POSITA would be familiar with the Mitutoyo liquid‑lens literature (e.g., US 2018/0314033 A1; US 2018/0314042 A1; US 2019/0121056 A1; US 2020/0073025 A1), which explicitly addresses temperature‑driven shifts in the liquid lens resonance and proposes resonance‑lock control — a fact that matters greatly to motivation, discussed in § 5.

Critical date: 2018‑08‑07 (Japanese priority JP 2018‑148386; adjusted expiration 2039‑10‑14).

2. Claim 1, element by element

Reconstructed from the Summary section (the verbatim claim‑support paragraph):

The technical core of 1.9–1.10 is a two‑point calibration of a periodically sweeping focus: the two reference portions sit at a known separation L, so the times at which the sweep crosses them let the system solve for the sweep's amplitude A, offset B, and phase delay φd (equations (5)–(8)), which are then used to correct the measurement‑side phase (equations (9)–(11)): Zcalc = (Fm/Fr)(B + A cos Φm1).

3. What each reference contributes

R1 — US 2010/0177376 A1 (liquid lens "lens system")

Anticipates/suggests 1.2 fully, and the well‑known pairing of the lens system with an objective lens on a common axis to form a variable focal length lens whose focus position is controllable by drive‑signal amplitude. The patent itself adopts R1's structure verbatim (compare R1's cylindrical piezoelectric oscillator immersed in liquid / standing wave / concentric refractive‑index regions against ¶¶ describing case 21, oscillating member 22, liquid 25, and refractive index distribution R). R1 supplies nothing about measurement, referencing, or calibration.

R2 — JP H11‑23219 (confocal laser displacement sensor)

Supplies 1.4, 1.7 (measurement branch), 1.8 (measurement‑side timing in kind), and 1.10's principle, in that it teaches:

• a confocal optical system in which the photodetection signal peaks when the focus position coincides with the object surface — the same peak‑timing detection mechanism the patent uses (the patent's specification states the peak of the photodetection signal is the focus timing);
• the concept that the detected focus timing/position encodes the object distance, and the object position is derived from the sweep state at that instant; and
• an objective lens as the final focusing element.

Its acknowledged drawback — a lens‑drive mechanism plus a scale — is the patent's own stated motivation for substituting the R1 liquid lens. That is a textbook "known problem, obvious solution" combination (R1 + R2).

R3 — JP 2009‑122105 (chromatic point sensor)

Supplies the calibration/correction architecture and the express design objective: the JP abstract and claim 1 (as indexed by J‑GLOBAL) recite a calibration memory holding index‑specific data‑limiting parameters and distance‑calibration data, with the stated purpose of giving the sensor "improved accuracy and robustness." R3 thus supplies:

• the idea of a calibration/correction table — the very thing the subject patent uses (calibration table 94 "prepared in advance using a target," FIG. 10) to map computed Zcalc to true Z;
• the express goal of robustness against intensity and detector‑bias variation; and
• the concept that a focus‑position sensor can be characterized by known reference points.

R3 is also useful for the "known focus‑detection method" teaching: the patent expressly concedes that "various focal point detection methods such as a confocal method, a double pinhole method, an astigmatic method, and a knife edge method" may be used — an admission that the timing‑detection mechanism is a design choice.

The gap

No one of R1–R3, alone or facially combined, discloses or suggests element 1.6's dual reference portion (nor 1.3's downstream beam splitter feeding a reference channel that passes through the same liquid lens apparatus, nor 1.9's "compute the lens's refractive‑index characteristics from the two reference timings").

4. Combination A (primary): R1 + R2 + R3

Proposed rejection: Claim 1 is obvious over R1 in view of R2, further in view of R3.

Element mapping

Motivation to combine (the crux under KSR). Three independent lines all point the same direction:

1. The patent's own admitted problem. The specification states that when a variable focal length lens is affected by time/temperature, "characteristics such as a variable range of a focal length may change," creating "a possibility that measurement accuracy may be reduced." A POSITA facing the admitted drawback of an R1‑based device has a clear reason to add calibration of the lens itself.

2. R3's express design objective. R3 was designed to give an optical focus‑position sensor "improved accuracy and robustness" through stored calibration parameters — the identical objective. KSR: "if a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious unless its actual application is beyond his or her skill."

3. Dual‑target referencing is a known, predictable technique in focus‑based metrology. Two known targets at a known separation to characterize a scanning/spectral focus sensor's amplitude, offset, and phase is the standard two‑point calibration that a POSITA applies as a matter of design course; the subject patent's own FIG. 10 calibration table, "prepared in advance using a target," shows the technique was already in the applicant's practice.

4. Predictable results / finite number of identified solutions. The patent's equations (5)–(8) are closed‑form algebra, not an unpredictable result. Given two returns from two known depths, solving for (A, B, φd) is the obvious solution with a finite number of implementation options. KSR: "a court must ask whether the improvement is more than the predictable use of prior art elements according to their established functions."

5. Combination B (stronger, if the art qualifies): applicant‑family art + R1

If the Mitutoyo liquid‑lens publications that predate the critical date qualify as § 102(a)(2) art (US published applications effectively filed before 2018‑08‑07), the case becomes materially stronger:

• US 2018/0314033 A1 and US 2018/0314042 A1 ("Variable focal length lens device / …control method") describe the R1‑type lens system and expressly recognize that "due to the effect of external air temperature or heat generation accompanying operation, the temperature of the liquid and the vibrating member inside the lens system changes," shifting the resonance frequency — and propose resonance‑lock control (a resonance‑lock controller / resonance‑lock operation unit) to track it. This is direct, same‑assignee evidence that a POSITA was already addressing exactly the drift the subject patent wants to correct, and it supplies an overwhelming motivation to detect and compensate the lens's varying operating point. It also introduces the notion of timing/measurement windows synchronized to the drive signal and of suspending lock during measurement — context closely related to the claimed benchmark‑signal scheme.
• US 2019/0121056 A1 and US 2020/0073025 A1 further develop lens‑system control (drive‑signal amplitude / effective‑power control).

Caveat — I flagged the dates: the A1 publications of these appeared after 2018‑08‑07, so they are prior art only if their effective filing/priority dates precede that date, which I could not confirm with the tools available. Verify before relying on them.

6. The closest art of all — and why it likely is not prior art

Searching revealed applicant's own sibling: US 2020/0041267 A1 / US 10,830,585 B2, "Non‑contact type displacement sensor" (Mitutoyo). It discloses a liquid‑lens variable‑focal‑length non‑contact displacement sensor with an objective lens, a photodetector, a focus‑timing calculator, a reference (benchmark) signal outputter synchronized with the drive signal, calculation of the focus timing from the peak of the photodetection signal, and calculation of the object position from the phase of the focus timing relative to the drive‑signal cycle — i.e., substantially the whole of claim 1 except the reference channel (1.3's split into reference light, 1.5–1.6's reference‑side objective lens and dual reference portions, and 1.9's characteristics calculator).

This sibling is the most probative art if it is available, because it establishes that the entire measurement architecture of claim 1 was already applicants' own prior development, leaving only the self‑calibration reference channel. However: on the information I have, this sibling shares the very same Japanese priority lineage (JP 2018‑148386, filed 2018‑08‑07) as the patent under analysis. If so, it is not prior art under § 102(a)(1) or (a)(2), and — because it is not by "another" inventor in the relevant sense — may not be usable at all. I could not confirm the priority/filing dates with the tools available; this must be verified against the face of US 10,830,585 and its file wrapper before use. If, contrary to expectation, its effective filing date predates 2018‑08‑07, it becomes the single most damaging reference.

7. Dependent claims

The dependent claims are, on the whole, weaker than claim 1 and fall with it.

8. Honest assessment of where the combination is strong and where it is weak

Strong for the challenger:

• Claim 1's measurement architecture (elements 1.1–1.2, 1.4, 1.7–1.8, 1.10) is essentially R1 + R2, combined for the reason the patent itself articulates (escape the R2 lens‑drive mechanism and scale).
• The objective of the characterizing feature (1.9) — robustness against time/temperature drift of the lens — is expressly the stated aim of R3 and of applicants' own resonance‑lock work, giving a nearly unassailable motivation.
• The mathematical method (two known depths → amplitude, offset, phase) is a predictable, closed‑form engineering solution, and the applicant's own calibration‑table practice shows reference‑target calibration was standard.
• The patent's specification contains numerous admissions that help: focus‑timing detection may use any of the confocal / double‑pinhole / astigmatic / knife‑edge methods; the end‑face‑as‑pinhole is conventional; the separate‑source/detector variant merely "simplifies computation."

Weak for the challenger (points the patentee will press):

• The specific combination 1.3 + 1.5–1.6 has no direct counterpart in R1–R3. Placing the beam splitter downstream of the liquid lens so that both channels share the same liquid lens, and then inferring the lens's own refractive‑index characteristics from two known‑depth reference returns, is not taught by the page's three references. The patentee will argue this is a non‑obvious architectural insight (it isolates the drift source rather than calibrating the end‑to‑end system, as R3 does).
• R3 calibrates with a table, not with a co‑swept reference arm. The patentee will distinguish static/prior calibration (R3's stored table) from real‑time, in‑situ self‑calibration using a reference arm swept by the same lens. That distinction is real and should be met head‑on.
• The personnel records / priority issue cuts both ways: if the sibling US 10,830,585 does not qualify as prior art, the challenger loses its best reference.

How the challenger bridges the weak points (the rebuttal to the patentee's distinction):

• The distinction between "prior table calibration" (R3) and "live reference arm" (claim 1) is a difference in degree/location, not in kind. Both use a known reference to correct a focus‑position measurement. Under KSR, "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results," and here the claimed result (a corrected Zcalc) is exactly what R3's calibration achieves, merely performed continuously.
• The downstream‑splitter architecture follows directly from the stated objective: to correct the lens's refractive‑index characteristics (1.9), the reference channel must see the same lens. Any POSITA pursuing self‑calibration of the lens would place the split downstream of the lens. This is "the predictable use of prior art elements according to their established functions."
• The embodiment breadth supports breadth of the combination: the patent covers both separate‑source (FIG. 1) and shared‑source (FIG. 14) topologies, and both mirror‑based and fiber‑based reference portions — evidence that the reference‑channel implementation was a routine design choice, not a point of novelty.

9. Secondary considerations

I found no evidence on the page of secondary indicia: no licensing, no commercial‑success nexus, no unexpected‑results data. The applicant's asserted advantage — "improved robustness" against time/temperature — is precisely the result a POSITA would expect from R3‑type calibration, so it cuts against, rather than for, non‑obviousness (expected, not unexpected, results). If the patentee later adduces commercial success of Mitutoyo non‑contact sensors, the nexus would be difficult to establish given the crowded field and the admitted advantages over R2/R3.

10. Recommended next steps for a higher‑confidence § 103 position

1. Obtain the full Google Patents "Citations" / "Cited By" / "Similar Documents" lists for US 10,948,334 (the fetched page was truncated; my analysis was necessarily confined to the three references in the Related Art section).
2. Verify the effective filing/priority dates of US 2020/0041267 A1 / US 10,830,585 B2, US 2018/0314033 A1, US 2018/0314042 A1, US 2019/0121056 A1, US 2020/0073025 A1. If any predates 2018‑08‑07, it is decisive.
3. Search the confocal/interferometric self‑calibration literature for dual‑reference‑surface characterization of a swept‑focus or spectrally‑encoded focus sensor (e.g., swept‑source OCT dual‑reference calibration; chromatic‑confocal two‑step calibration; autofocus with reference beam). Such art would close the only remaining element‑gap (1.6/1.9) directly.
4. Pull the file wrapper of US 10,948,334 to see exactly which references the examiner cited under § 102/§ 103 and which arguments were made — the prosecution history will reveal the examiner's own view of the R1/R2/R3 combination.

Bottom line

On the record available, claim 1 is vulnerable to a § 103 rejection over R1 (US 2010/0177376) in view of R2 (JP H11‑23219), further in view of R3 (JP 2009‑122105) — the first two supply the liquid‑lens‑based confocal displacement architecture the patent admits was the object of the exercise, and R3 supplies both the calibration/correction architecture and an express "accuracy and robustness" motivation that maps directly onto claim 1's characteristics calculator → position calculator correction loop. The only element not squarely met by the three page‑cited references is the dual‑reference‑portion reference channel whose returns characterize the liquid lens itself (elements 1.6 and 1.9). That gap is narrow and, in my assessment, bridgeable with (i) the well‑known two‑point calibration of a scanning focus sensor and (ii) same‑assignee art (US 2018/0314033 / US 2018/0314042) showing the field already recognized and addressed temperature‑driven drift of the very lens at issue — provided that art's effective filing dates precede 2018‑08‑07, which I have flagged as unverified. The dependent claims add only predictable design choices that the specification itself justifies on computational or cost grounds, and would fall with claim 1.

Confidence: moderate‑to‑high on the motivation to combine and on the § 103 attack on the measurement architecture; lower on the element‑by‑element anticipation of the dual‑reference‑portion channel, where additional art and date verification are needed. I have not verified the full claim set (only claim 1 and the "preferably" dependents were recoverable from the fetched text) or any litigation/PTAB record (per the prior section, none appears to exist).