US 10215684

I'll search for the patent on USPTO and check for any CAFC/litigation activity.

Let me check for litigation or PTAB activity involving this patent specifically.

Let me do one more targeted check for any docket activity.

US Patent 10,215,684 — Analyst Summary

Verification basis: Text below is taken from the authoritative full patent document supplied for US10215684B2 (Google Patents, fetched 2026-09-24). I also ran open web searches for USPTO PatentCenter status and CAFC 2026 docket activity. I could not query PatentCenter or the Federal Circuit docket systems directly — only via general web search — so the litigation/docket portion carries that limitation and is flagged accordingly.

1. Bibliographic data

2. Abstract (verbatim)

"A fine particle detection device according to the present disclosure includes: a first irradiation portion configured to radiate excitation light to a flow passage in which a fine particle flows to excite fluorescent light from the fine particle; a first separation portion configured to separate the excitation light and the fluorescent light from light that has been radiated to the flow passage by the first irradiation portion; a first detection portion configured to detect the fluorescent light separated by the first separation portion; a second irradiation portion configured to radiate the excitation light separated by the first separation portion to the flow passage to excite the fluorescent light from the fine particle; a second separation portion configured to separate the excitation light and the fluorescent light from light that has been radiated to the flow passage by the second irradiation portion; and a second detection portion configured to detect the fluorescent light separated by the second separation portion."

3. Plain-language overview of the claims

There is exactly one independent claim (claim 1); every other claim is a dependent claim that narrows it. So the independent-claim burden falls entirely on claim 1.

Claim 1 (independent) — the core "light-recycling" concept

A flow-cytometer-style fine-particle detector that reuses its own excitation light:

1. A first irradiation portion shines excitation light (e.g., laser) at a flow passage carrying a particle, exciting fluorescence from the particle.
2. A first separation portion takes the light coming off that first irradiation spot and splits it into (a) excitation light and (b) fluorescence (the spec uses a PLC planar-lightwave-circuit spectroscopic element with a grating in an optical waveguide).
3. A first detection portion measures the fluorescence from step 2.
4. A second irradiation portion takes the excitation light separated out in step 2 and shines it back onto the flow passage to excite fluorescence again (downstream, at a second spot).
5. A second separation portion again splits light from that second spot into excitation light and fluorescence.
6. A second detection portion measures the fluorescence from step 5.

Plain language: instead of throwing away the laser light that missed a cell, the device catches it, filters out the fluorescence, and sends the leftover laser back at the stream for a second measurement — so essentially the same optical input is interrogated twice.

Dependent claims (all depend on claim 1)

• Claim 2 — a lens that refracts the excitation light going to, or the light coming from, the flow passage is shared in common by the first and second irradiation portions (one lens serves both detection spots).
• Claim 3 — a beam-shaping portion that shapes the excitation light is shared in common by the first and second irradiation portions.
• Claim 4 — the first and second detection portions are implemented as one common detection portion (a single detector/photodetector serves both spots).
• Claim 5 — the first separation portion has multiple fluorescence output portions (e.g., fluorescence split into two ports), and the first detection portion has multiple detection portions with different characteristics (spec examples: a PD with wide dynamic range and an MPPC with weak-light sensitivity) reading those outputs.
• Claim 6 — the same "split fluorescence into multiple outputs feeding detectors of different characteristics" feature, but applied to the second separation/detection side.
• Claim 7 — both sides have multiple fluorescence outputs and multiple detection portions, and at least one detector from the first group and one from the second group are a common (shared) detector.
• Claim 8 — the first and second irradiation portions each include an optical waveguide (e.g., optical fiber) used to deliver excitation light to the flow passage.
• Claim 9 — those two irradiation waveguides are adjacent to each other along the particle flow direction.
• Claim 10 — those two irradiation waveguides are an integrated optical fiber ribbon (multiple cores side-by-side; spec cites ~250 µm core pitch, ~12.5 µm spot spacing at 20× magnification).
• Claim 11 — instead of the delivery waveguides: the first irradiation portion includes a first optical waveguide transmitting collected light from the flow passage to the first separation portion, and the second irradiation portion includes a second such waveguide to the second separation portion (i.e., the collection side, not the illumination side).
• Claim 12 — those two collection waveguides are adjacent along the flow direction.
• Claim 13 — those two collection waveguides are an integrated optical fiber ribbon.

4. Technical points worth noting for prosecution/validity analysis

• Stated problem: in a conventional cytometer (Fig. 2) the beam spot is deliberately elongated perpendicular to flow (Fig. 1), so most laser light misses the cell and is simply absorbed by the emission filter → poor excitation-light utilization. The patent's fix is the recycle-and-remeasure architecture of claim 1.
• Why the recycled light is still usable: the spec argues excitation light that did not hit a cell is largely unchanged in polarization and other characteristics, so it can be separated and re-used; light that did hit the cell may have its polarization changed, making perfect separation difficult.
• Shared-optics benefit (Figs. 5 and 7): because the two irradiated spots can be placed very close, the lens 102, beam shaper 104, lens 105, lens 108, and even the emission filter 110 and high-sensitivity detector 114 can be common to both detection spots — asserted as improving S/N without added cost.
• Timing argument: with 50–100 cm of optical path between spots, recycled light arrives in ~150–300 ps, while a cell at 20 m/s moves only ~0.003–0.006 µm — so the two detections are treated as effectively simultaneous and the same cell is measured twice. Worked example: 12.5 µm spot separation and 2.5 µm window width → 22.5 µm total span vs. ~400 µm inter-cell spacing (i.e., well under half).
• Note on claim 7 terminology: in the issued claim the reference numeral/label scheme ("plurality of first detection portions") is slightly awkward, since the claim language uses "first detection portion" both as the single recited element and as a plurality — a potential §112(b) argument hook, though I have no authoritative record of any such challenge being raised.

5. Litigation / CAFC docket check — result and uncertainty

• No CAFC 2026 appeal or district-court/PTAB proceeding involving US 10,215,684 was found in my searches. Searches of Federal Circuit 2026 round-ups (including the WilmerHale and IPWatchdog/Obon case summaries) surfaced only unrelated Sony-related appeals — e.g., Intellectual Pixels Ltd. v. Sony Interactive Entertainment LLC (US 10,681,109, claims 1–12 affirmed unpatentable) — and other Sony IPR matters (IPR2023-00324, IPR2024-00925), none of which concern the '684 patent.
• One caution: a search returned a Brazilian exam-result PDF (CEBRASPE concurso listing) containing the string "10215684" as a candidate registration number. That is not this patent and should be disregarded — it is a coincidental numeric match, not a patent identifier.
• Uncertainty statement: I could not directly query USPTO PatentCenter, the PTAB docket, or the CAFC docket; my only access was general web search. Therefore the absence of litigation/appeal activity is a negative search result, not an affirmative certification that none exists. If a definitive litigation history is required, it should be confirmed against PatentCenter's "Legal Events"/assignment tab, the PTAB Patent Trial & Appeal Board End-to-End docket, and the Federal Circuit's CM/ECF/RSS docket for this patent number.

6. Bottom line

US 10,215,684 (Sony, Kishima) is a granted, currently-active flow-cytometry patent with a single independent claim (1) covering capture, separation, and re-irradiation of unused excitation light at a second detection spot, plus twelve dependents that layer on shared optics (lens, beam shaper), a shared detector, multi-port fluorescence splitting to detectors of differing characteristics, and adjacent/ribbon-integrated optical waveguides on the illumination and collection sides. Family members are JP 2017083263A and WO2017073143A1. No US or CAFC litigation/appeal activity for this specific number was found, subject to the database-access limitation noted above.

I'll search for litigation involving US patent 10215684.

Let me run more targeted searches on litigation-specific databases.

Let me try a few more targeted searches on litigation databases.

Litigation Report: US Patent No. 10,215,684

Search Summary

I searched for litigation specifically involving US 10,215,684 (the "Fine particle detection device" patent, invented by Koichiro Kishima, originally assigned to Sony Corp). Queries were run across litigation-oriented sources (RPX/Unified Patents-style litigation aggregators, PACER-derived dockets, CourtListener, and general case-law searches), and I looked for the exact identifiers "10215684," "10,215,684," and the granted claim text.

Finding: No litigation identified

I found no litigation involving US 10,215,684.

Specifically:

• No district court complaint, declaratory judgment action, ITC investigation, or PTAB proceeding (IPR/PGR/CBM) asserting or challenging this patent appeared in any search result.
• The searches surfaced only unrelated cases against Sony entities that assert different patents (e.g., Tau Ceti Ventures LLC v. Sony Group Corp., C.D. Cal. 3:26-cv-03738, asserting U.S. 8,101,959 / 8,492,780 / 8,766,309 / 9,257,604 / 9,847,460 / 10,038,116 / 10,439,108; Control Sync Systems, LLC v. Sony Electronics Inc., E.D. Tex. 2:25-cv-00896; SensoSure LLC v. Sony Group Corp., E.D. Tex. 2:26-cv-00177; WFR IP, LLC v. Sony Electronics, Inc., E.D. Tex. 2:25-cv-01057; Volteon LLC v. Sony Electronic Inc., E.D. Tex. 2:25-cv-00094; IngenioSpec, LLC v. Sony Group Corp., E.D. Tex. 2:24-cv-00820; and Neodron Ltd. v. Sony Corp., W.D. Tex. 6:20-cv-00122). None of these lists US 10,215,684 among the asserted patents (per the docket AO-120 forms/reports reproduced in the results).
• The only appearance of US 10,215,684 in the results is as an inventory/palette entry on a patent-ranking site (Patent Leaderboard, listing it among inventor Koichiro Kishima's ~97–99 Sony patents), not as the subject of an enforcement action.

Case-by-Case Table

Confidence and Caveats

• Confidence level: moderate-to-high that no litigation involving this specific patent exists, but I cannot state this with absolute certainty. The underlying web searches did not return comprehensive coverage from a single authoritative litigation database (e.g., I could not fully render a Unified Patents litigation caselist page or a Docket Navigator/RPX case page keyed to this patent number during the searches).
• The patent issued February 26, 2019, from an application filed August 18, 2016 (U.S. National Phase of PCT/JP2016/074159; priority JP 2015-210980), and is listed as Active with maintenance fees paid (4th-year fee paid 2022). Its family is small and, based on the record retrieved, it does not appear to have been asserted.
• To verify definitively, I recommend a direct query of:
  • Docket Navigator (patent-level "Patent Litigation" tab)
  • RPX Insight / Unified Patents Portal litigation caselist, keyed to patent number 10215684
  • USPTO Patent Trial and Appeal Board (PTAB) proceeding search on the patent number
  • PACER docket text search for "10,215,684"

Per your strict rule, I am reporting only the literal identifier US 10,215,684 and not inferring from any similarly numbered patents (e.g., non-U.S. 10215684 or other patents in Sony's portfolio). I did not find any matching case to list.

I'll start by verifying the structured data's "no PTAB activity" default against live sources.

No hits yet. Let me run more targeted queries on the patent number, its family members, and the PTAB docket.

Let me do a final confirmation pass on the PTAB docket and any litigation that would have spawned an IPR.

Proceedings overview

Total AIA trial proceedings on file for US 10,215,684: zero. The USPTO Open Data Portal (ODP) structured "PTAB proceedings on file" block returns no AIA trial proceedings for this patent as of the most recent ingest — no IPR, PGR, or CBM, in any status (no active trial, no claims invalidated, no claims sustained, no settlement, no institution denial). Independent web searching surfaced no PTAB petition, Final Written Decision, or Federal Circuit appeal naming this patent, its application number 15/767,767, its pre-grant publication US20180306697A1, or its WO/JP family members (WO2017073143A1, JP2017083263A). The bottom-line defensive posture: the patent is untested at the PTAB and therefore unhardened but also uncontaminated — there is no claim-level estoppel record, no cancelation to exploit, and no PTAB-tested claim construction to lean on. A defendant here is litigating against a pristine patent with a live presumption of validity, not against a survivor of an invalidity gauntlet.

Important caveat on the "zero" figure. The absence of PTAB activity is a genuine finding, not a proof of nonexistence. The ODP ingest may lag recent filings, and IPR petitions are often filed near the § 315(b) one-year bar and may not be publicly indexed immediately. I could not complete a final confirmation pass on the PTAB docket (search budget was exhausted), so a recently filed petition that ODP hasn't yet indexed cannot be ruled out with certainty. Treat the count as "zero as of the most recent ODP ingest," and re-verify against PTAB E2E before relying on it in a filing or opinion.

No proceedings to report

Because the structured data contains no proceeding numbers, there are no IPR20XX-XXXXX — Petitioner v. Sony Corporation entries to build out. I will not invent proceeding numbers, judge panels, grounds, or dispositions. Every field below would be fabricated, so all are recorded as absent:

Distinguish carefully: US 10,215,684 is a Sony-owned patent (assignee Sony Corporation; inventor Koichiro Kishima; U.S. national phase of PCT/JP2016/074159, JP priority 2015-10-27). Sony appears frequently on the petitioner side of PTAB proceedings against other parties' patents, and my searches returned several such documents. Those Sony-as-petitioner matters involve entirely different patents and are not proceedings against US 10,215,684. Do not conflate them.

Strategic summary

Claim status: 100% UNTESTED. All thirteen claims stand as issued on 2019-02-26 — claims 1–13, including independent claim 1 and the "irradiation portion / separation portion / detection portion" architecture, plus dependent claims 2–13 covering the common lens (claim 2), the common shaping portion (claim 3), the common detection portion (claim 4), the multi-output-portion / differing-characteristics detection splits (claims 5 and 6), the shared common detection sub-portion (claim 7), the optical waveguides for radiating excitation light (claims 8–10), and the optical waveguides for transmitting light to the separation portions (claims 11–13). None is canceled, none was adjudicated, and none has been narrowed by a PTAB-held construction. The only narrowing of record is whatever occurred during prosecution of application 15/767,767 — and notably, the granted claim language differs textually from the originally-filed claim set (e.g., claim 2 was rewritten from an "or" list to a three-option closed list; claim 11 was rewritten with "first"/"second" optical waveguides and "third"/"fourth" light, and "configured to" was inserted). Those claim-differentiation edits are a useful prosecution-history target, but they are your work product to develop — no PTAB panel has done it for you.

Estoppel landscape: a blank slate, which cuts both ways. Because there are no proceedings, § 315(e)(2) IPR estoppel and § 325(e)(2) PGR estoppel bar nothing against anyone. No prior-art ground has been "raised or reasonably could have been raised" before the Board, so a defendant's full invalidity case — every § 102 and § 103 combination, every § 112 written-description or enablement theory — remains available in district court. Conversely, you also have no free shot: with no prior IPR on this patent, there is no argument that the art was already before the Office, and you would be the first to ask the Board to invalidate. The practical consequence is that the § 315(b) one-year clock is the operative constraint: if this patent is ever asserted against you, you must decide on a petition within one year of service of the complaint. Because there is no earlier petitioner and no prior panel construction, you would bear the full burden of building an institution-quality record from scratch.

Pattern signals: none of the usual markers. No single petitioner has filed multiple IPRs against this patent (there are no petitioners at all). The patent owner, Sony, has not pursued PTAB appeals on this patent (there are no FWDs to appeal). There is no defensive aggregator — no Unified Patents, RPX, or similar entity — in the chain, which is consistent with this being an operating-company patent in a technical flow-cytometry niche rather than an NPE-funded assertion target. The absence of PTAB activity is itself informative: well-asserted patents eventually attract IPRs, and the absence of any petition over roughly a decade of enforceability suggests this patent has not been broadly asserted in litigation. That is a signal about assertion posture, not a validation of the claims — the claims have simply never been stress-tested.

Recommended next steps

If you are a defendant facing assertion of US 10,215,684:

1. Do not expect to inherit an invalidity win. There is no FWD to cite, no canceled claim to point to, and no litigation-estoppel payoff from a prior PTAB case. Any argument that "the claims have already been invalidated" would be false and, if advanced, sanction-bait.
2. Take your own claim-level view of claim 1 as the primary target. The independent claim is a system claim built on five functional blocks — first irradiation portion, first separation portion, first detection portion, second irradiation portion fed by the excitation light separated by the first separation portion, and second separation portion plus second detection portion. The re-use of separated excitation light is the apparent point of novelty over the cited JP 2012-26837A (the background-art optical-filter reference). The strongest § 103 theories will likely attack the "second irradiation portion configured to radiate the excitation light separated by the first separation portion" recirculation element directly.
3. Mine the prosecution history of 15/767,767 before doing anything else. The granted claims differ from the as-filed claims in ways that suggest examiner-driven narrowing. Whatever was argued to overcome rejections is a potential prosecution-history-disclaimer or estoppel anchor under Phillips and its progeny. This is the single highest-value document in the file right now.
4. Confirm the PTAB docket yourself before relying on the zero count. Run the patent number, application number 15/767,767, and the family (WO2017073143A1, JP2017083263A) through USPTO PTAB E2E and Patent Center, and check CourtListener for any CAFC appeal referencing the patent or the PCT. My search budget ran out before a final docket sweep; the ODP block is the canonical source and it reports nothing, but a last-mile verification is cheap insurance.
5. Watch § 315(b) timing. If you are served, the one-year petition window is strict and non-extendable, and there is no co-petitioner or prior filer to join. Decide early whether to file or to waive PTAB entirely.
6. Note the expiration date of 2036-08-18 (per the ODP legal-status data, from the 2016-08-18 filing date). Maintenance fees were paid through the 4th year (payment recorded 2022-08-31, with a late-payment surcharge). A long remaining term increases the value of an early invalidity challenge and reduces the value of simply waiting the patent out.

If you are the patent owner: the absence of any IPR is a favorable data point — no claim has been canceled or narrowed by the Board, and the patent carries an undisturbed presumption of validity. But it also means the claims are untested, and you should assume that any meaningful assertion will draw a § 102/§ 103 petition. Consider having a defensive claim-chart and a validity position prepared before asserting, since the first petition against this patent will be filed without the benefit of any prior Board guidance on the claim terms.

I'll start by verifying the assignment records and checking for any litigation or NPE involvement.

Let me verify the assignment record details and check Sony's product line for this technology.

Ownership Reconstruction — US 10,215,684 B2 ("Fine particle detection device")

Data-source caveat up front: the assignment facts below are taken from the Google Patents legal-events feed embedded in the authoritative patent text supplied, which exposes reel/frame, execution date, recording date, assignor and assignee. That feed does not carry the correspondent-of-record field, and my attempt to pull the Assignment Center record live (patent number 10215684) was cut off by a tool limit before I could read it. I am therefore explicitly declining to name a correspondent rather than infer one. Everything else below is sourced; nothing is reconstructed.

Inventors

Unusual-pattern check: no. There is only one inventor, so the "all inventors depart within 12 months" fire-sale tell is structurally inapplicable. Kishima's filing record shows continuous Sony-assigned output spanning well before and after the 2015-10-27 priority date, which is the signature of a career operating-company inventor, not a bolting one. I could not verify his current (2026) employment — flagging that as unverified.

Original assignee

Sony Corporation (Tokyo, JP) — named as assignee on the issued patent and as "Original Assignee" and "Current Assignee" in the Google Patents record.

• Primary line of business: diversified consumer electronics and entertainment, including a life-sciences instrumentation arm (Sony Biotechnology) that commercializes flow cytometers / cell sorters and spectral analyzers — i.e., the exact device class this patent describes (laser excitation → fluorescence detection on a flow passage). Confidence note: I did not get a search result confirming the current Sony Biotechnology product line before hitting the tool limit; this rests on my prior knowledge and should be spot-checked. It is material to the "does the assignee ship a product" question.
• Status: operating, listed company; no bankruptcy proceeding. One ownership nuance worth manual verification: effective 2021-04-01 Sony Corporation was reorganized — the listed parent became Sony Group Corporation and a successor entity took the "Sony Corporation" name. A pure name change of this kind is normally not recorded as an assignment, which is consistent with the single-record chain below, but the assignee of record "Sony Corporation" is not necessarily the same legal person as the pre-2021 Sony Corporation. I assess this as likely correct but have not verified it against a USPTO record in this session.

Assignment timeline

Chronological list of every recorded assignment:

• 2018-03-02 (executed) / recorded 2018-04-12 — Reel 045520/0609
  • Conveyance: Assignment — recorded as "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)"
  • Assignor: KISHIMA, Koichiro
  • Assignee: SONY CORPORATION, JAPAN
  • Correspondent: not exposed in the legal-events feed; not retrieved from Assignment Center in this session — do not treat as blank, treat as a data gap.
  • Context: inventor-to-company assignment perfecting title for the US national-phase (35 U.S.C. § 371) filing of PCT/JP2016/074159; a prosecution formality, not a third-party transfer.

There are no post-issuance assignments of record. The only other legal events are administrative, not conveyances:

Family: only three members — US 15/767,767 (this patent), JP 2017083263A, WO 2017073143A1. No continuation or divisional chain carrying separate ownership.

Timeline diagram

timeline
    title Ownership of US 10215684
    2015 : JP priority application filed
    2016 : PCT application filed Aug 18
    2018 : Inventor assignment recorded
         : Assigned to Sony Corporation
    2019 : US patent issued Feb 26
    2022 : Maintenance fee paid year 4
    2026 : No further assignments recorded

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT.
The sole recorded conveyance is Kishima → Sony Corporation at reel 045520/0609. No "IP / Patents / Licensing / Holdings / Ventures" entity appears anywhere in the chain. This is a meaningful negative rather than a default: Sony has historically run exactly this playbook. In the same assignor's other paper, Sony → SCA IPLA Holdings Inc. → MobileMedia Ideas LLC was recorded 2010-01-21 at reels 023828/0473 and 023828/0504 for legacy audio patents. That a known Sony NPE-transfer pipeline exists, and that US 10,215,684 has never entered it, is affirmative evidence against this signal.

2. Known asserter in the chain — NOT PRESENT.
No assignee or assignor matches any public NPE list (Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Round Rock, etc.). The chain begins and ends at Sony Corporation. Target searches for "10215684" combined with litigation/complaint/plaintiff terms returned no infringement suit naming this patent.

3. Repeat correspondent across the chain — UNCLEAR.
Not assessable. There is only one recorded assignment, so "recurrence" is impossible to establish within this chain by construction, and the correspondent field was not retrievable in this session. This is the single most important open item — pull reel 045520/0609 at Assignment Center and record the filing attorney/firm, then check that name against this site's other tracked patents. Note the operating rule: a single appearance by a firm that does both operating-company and NPE work is not a finding.

4. Cascading transfers — NOT PRESENT.
One assignment in the ~7.5 years since grant and ~10 years since priority. No chained LLCs, no sub-24-month sequences, no shared correspondent addresses.

5. Pre-litigation transfer — NOT PRESENT.
No infringement suit identified. The single assignment executed 2018-03-02 and recorded 2018-04-12, roughly a year before issue (2019-02-26) and over three years before the only notable post-grant event (2022 maintenance payment). There is no enforcement chronology for a transfer to precede.

6. Bankruptcy fire-sale — NOT PRESENT.
Sony Corporation has no Chapter 7/11 proceeding, and no judicial-sale or 363-sale conveyance appears on the record.

7. Privateering — NOT PRESENT for this patent.
No transfer to an NPE asserting on Sony's behalf. See the MobileMedia contrast in signal 1: the vehicle existed, and this patent was not put into it.

8. Defensive aggregator (anti-NPE) — NOT PRESENT.
The chain terminates at Sony Corporation, an operating company. It does not terminate at RPX, AST, LOT Network, Unified Patents or OIN, so the patent has not been neutralized by defensive aggregation — correct the common misreading that "no assignments" equals "defensively parked."

Adjacent observation (weak, offered as context not as a signal): the 4th-year maintenance fee was paid late with a surcharge (2022-08-31). A large-entity operating company paying on the grace-period side is mildly inconsistent with an active assertion-licensing program, but this is an inference from administrative data and I would not weight it.

Verdict

Insufficient data (no records beyond the original assignment).

Substantively, the affirmative evidence points one direction and only one: US 10,215,684 is a clean, single-link operating-company chain. The entire recorded history is a § 371 inventor-to-company assignment — Kishima → Sony Corporation, executed 2018-03-02, recorded 2018-04-12 at reel 045520/0609 — with no post-issuance transfer, no LLC intermediary, and no litigation naming the patent in any search I ran. That is the opposite of every NPE signal on the checklist. I nevertheless select Insufficient data rather than a clean bill of health because the menu's definition ("only the original assignment") is literally met, and because two verifications remain outstanding: the correspondent of record on reel 045520/0609, and confirmation that Sony's current flow-cytometry line reads on the claims. Absent a second recorded link, the repeat-correspondent signal — the highest-value tell in this exercise — cannot be evaluated at all.

Verify at: USPTO Assignment Center — search patent number 10215684 and pull reel/frame 045520/0609 for the correspondent field; status cross-check at Patent Center for application 15/767,767.

I'll verify the patent record and its cited prior art through the USPTO and related sources.

Now let me look at the remaining cited references, particularly the two examiner-cited ones and the KDD optical amplifier reference.

Let me pinpoint the KDD reference JPH1187823A, which is the most obscure citation.

Prior-Art Analysis — US 10,215,684 B2

Note on identifiers: All numbers below are reported exactly as they appear in the record. I have not normalized or corrected any of them. Where I could not retrieve full text of a reference, I say so explicitly.

1. The subject patent (anchor)

Core inventive concept (claim 1): excitation light is delivered to a flow passage (first irradiation portion), light from that spot is split into excitation vs. fluorescence (first separation portion), fluorescence is detected (first detection portion), and — the distinguishing step — the separated excitation light is re-radiated to the flow passage to excite fluorescence again (second irradiation portion), then split and detected again (second separation portion / second detection portion). In other words, the unconsumed excitation light is recycled for a second interrogation point on the same particle.

That recycling/re-radiation limitation is the gating element for all § 102 analysis below.

2. The citations of record

The Google Patents record for US 10,215,684 lists these patent citations (and a family of equivalents). The "†/*" annotations in the fetched text were inconsistent between the two tables on the page; the "Citations (3)" table flags US 2012/0018650 A1 and WO 2013/114333 A1 with the examiner-citation marker. I present all ten plus the sole non-patent citation.

2.1 US 2012/0018650 A1 — Sony — "Fine particle measuring device" (examiner-cited)

• Full citation: US 2012/0018650 A1, "Fine particle measuring device," Sony Corporation; inventors Mitsuru Toishi, Katsuhiro Seo, Koji Takasaki, Shinji Yamada, Atsushi Fukumoto. Priority 2010-07-22; published 2012-01-26. Same family: JP 2012-026837 A (pub. 2012-02-09), CN 102346145 A (pub. 2012-02-08). The granted U.S. counterpart is reported by FreePatentsOnline as US 8,466,435 ("Fine particle measuring device," Sony Corporation).
• Brief description: An optical filter divided into a plurality of areas is placed on the optical path that guides light from an irradiated fine particle to an optical detector. A first area has wavelength selectivity that blocks reflected light and unnecessary scattered light but transmits fluorescence; a second area surrounding it has no wavelength selectivity and transmits the necessary scattered-light component. An optical fiber guides fluorescence and backscattered light to a fluorescence/backscatter detector. This is the "Patent Literature 1" (JP 2012-26837A) expressly discussed in the Background Art of US 10,215,684.
• § 102 assessment: This is the closest field reference — same assignee, same problem space (separating fluorescence from excitation/scattered light at the detector). It is directly relevant to the "first separation portion" and "first detection portion" concepts in claim 1, and arguably to claim 11 insofar as it discloses an optical fiber that transmits collected light to a separation/detection stage.
• Anticipation: No claim is anticipated. The reference uses the excitation light only once; it contains no second irradiation portion, no re-radiation of the separated excitation light to the flow passage, and no second separation/detection point. Claim 1 therefore is not § 102-anticipated by this reference. Its role is § 103 background over which the recycling concept was found non-obvious enough to grant.

2.2 WO 2013/114333 A1 — C-CAMP — "Microfluidic flow analyzer for pathological detection and method thereof" (examiner-cited)

• Full citation: WO 2013/114333 A1, Centre for Cellular and Molecular Platforms (C-CAMP); inventors Taslimarif Saiyed, Sudip Mondal, Anil Prabhakar, H. Krishnamurthy. Priority IN 4067/CHE/2011, 2012-02-04; PCT/IB2013/050871 filed 2013-02-01; published 2013-08-08.
• Family members also cited: EP 2810063 A1 (pub.

I'll ground this analysis in the actual prior-art references of record on the patent page, then verify their content.

Let me pin down the third reference of record and check a couple of the page's related prior-art documents.

Obviousness Analysis — U.S. Patent No. 10,215,684 B2

"Fine particle detection device" · Sony Corp. · Inventor: Koichiro Kishima · Priority: 2015‑10‑27 · Filed (PCT): 2016‑08‑18 · Granted: 2019‑02‑26

Grounding note: this analysis uses only the prior‑art references listed on the patent page itself (https://patents.google.com/patent/[US10215684](/patent/US10215684)/en), supplemented by content I retrieved for those references. I flag below the one reference whose specification text I could not verify.

1. The claim at issue (claim 1), element by element

Note what claim 1 does not require: no recitation of a PLC/grating, no adjacency dimension, no shared lens or filter, no common detector, no timing/synchronization of the same cell. The single limitation that carries the claim is (d) — the second irradiating beam must consist of the excitation light recovered by the first separation portion.

No single reference of record discloses (d). Elements (a)–(c) are old; (b)+(e) together with (a)+(d)+(f) form the novel architecture. Accordingly, the rejection posture here is §103, not §102.

2. What the prior art of record actually teaches

2.1 US 2012/0018650 A1 (Sony) — family of JP 2012‑26837 A / CN 102346145 A ("Patent Literature 1" of the patent); a granted counterpart appears to be US 8,466,435 B2

Source: https://patents.google.com/patent/US20120018650

• Fine‑particle/flow‑cytometer measuring device with an optical filter divided into a plurality of areas on the optical path from the particle to the detector; the filter has a first area with wavelength selectivity that blocks reflected light and unnecessary scattered light but transmits fluorescence, and a surrounding second area with no wavelength selectivity transmitting a necessary scattered component (claim 1 of that document).
• Expressly discloses using an optical fiber on the optical path so that "light transmitted through the optical filter is received by the optical fiber," the divided filter being arranged so the fiber receives that light — i.e., wavelength‑selective separation of fluorescence from excitation/reflected light, coupled into a waveguide and delivered to a detector.
• Also discloses a reflective filter variant (FIGS. 7A/7B) in which selected wavelengths are reflected rather than transmitted — establishing that the art treats the rejected (excitation) light as a light beam that is physically redirected on an optical path.
• Commercial purpose stated: "a fine particle analysis device that efficiently acquires back scattered light and fluorescence" — i.e., the same efficiency/sensitivity objective as the patent in suit.

What it lacks: any second irradiation stage, any reuse of the blocked/rejected excitation light, any second separation/detection occurrence.

2.2 WO 2013/114333 A1 (Centre for Cellular and Molecular Platforms, "C‑CAMP") — analogues US 2014/0374630 A1 and US 9,304,122 B2

Sources: https://patents.google.com/patent/WO2013114333A1 ; https://www.freepatentsonline.com/y2014/0374630.html ; https://patents.google.com/patent/US20140374630

This is, on the record, the closest art on the architectural question:

• A microfluidic flow analyzer with a central flow channel and plurality of exciting optical channels (FR1, FR2; F1) each coupled to a fibre‑coupled laser source, and plurality of receiving optical channels (FR3, FR4; F2, F4b) each carrying a detector (APD, Si‑PMT‑based photodetector, fibre‑coupled InGaAs detector, silicon avalanche photodiode, etc.).
• Wavelength‑selective filtering inside the collection waveguide: "F2 is configured with a Fibre Bragg grating to filter laser light emitted from the second exciting optical channel (F1)" — i.e., a separation portion that removes the excitation wavelength from the collected light so fluorescence is detected.
• Two spatially separated detection locations along the flow direction of a single channel, correlated to the same cell: "A second pair of optical fibres is placed further downstream of the fluid channel and the D.C. voltage from that circuit is also fed to the micro controller. The micro controller has a clock that will measure the time difference between the two comparator signals and calculate the velocity of the cell."
• Plural excitation channels arranged at defined angles to the flow channel, and a plurality of detectors on a plurality of receiving channels, with all detected signals sent to a common computing unit for analysis.

What it lacks: the second exciting channel is driven by its own fibre‑coupled laser source; the document never recovers the excitation light rejected at the first station and re‑radiates it downstream.

2.3 JP H11‑87823 A (Kokusai Denshin Denwa Co. Ltd. (KDD)) — "Optical amplifier," priority 1997‑09‑08, published 1999‑03‑30

Source (bibliographic only): cited on the patent page at https://patents.google.com/patent/US10215684/en

Verification limitation — stated plainly: I confirmed only the bibliographic record (assignee KDD, priority 1997‑09‑08, publication 1999‑03‑30, title "Optical amplifier"). I could not retrieve the specification text within this session, so I will not assert what it discloses. What I can say is that the examiner placed it in the record, and that KDD's contemporaneous work in this area concerned wavelength‑demultiplexing elements, optical circulators/selective reflectors and optical loop/fibre‑coupler feedback arrangements in which light separated by wavelength is routed back into the optical path (see, e.g., the separate KDD document EP 0 829 979 A3, priority 1996, describing a demux → amplifier → mux → fibre coupler loop with one output fed back to the demultiplexer input). That is context, not proof of what JPH1187823A teaches, and any office action relying on it would need its supporting passages identified.

3. The difference to be bridged

Claim 1 = Sony '650 (wavelength‑selective separation of fluorescence and excitation light, waveguide‑guided detection) plus C‑CAMP (multiple, longitudinally separated fibre‑coupled excitation/collection stations on one flow channel, with in‑fibre filtering of the laser wavelength and common signal processing of the same cell across two downstream‑spaced fibre pairs) plus one further step: the beam fed to the second excitation fibre is the excitation light recovered by the first separation portion.

That further step is the whole case. It is a classic §103 question, not a §102 question.

4. Ground of rejection #1 (primary): Sony '650 + C‑CAMP + JPH1187823A

Proposed rejection: Claim 1 is unpatentable under 35 U.S.C. §103 over US 2012/0018650 A1 in view of WO 2013/114333 A1, and optionally further in view of JP H11‑87823 A.

Rationale 1 — Combining known elements according to known methods, predictable result (MPEP §2143(A); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007)):

• Both references are in the same technological field (optical investigation of individual particles/flow cytometry; CPC G01N15/14, G01N15/1434, G01N21/64) and cite each other's subject matter. Sony '650 supplies the separation function (wavelength‑selective element + waveguide‑coupled detection), C‑CAMP supplies the repetition along the flow path function (multiple fibre‑coupled excitation/receiving channels, downstream second fibre pair, common processing).
• Placing a second, wavelength‑selective detection station downstream of the first in a single flow channel is not a change in the principle of operation of either system. Each retains what it was designed to do: illuminate the particle and detect fluorescence while suppressing the excitation wavelength.

Rationale 2 — Use of a known technique to improve a similar device in the same way (MPEP §2143(C)), and design incentive / market forces (MPEP §2143(F)):

• Sony '650's stated purpose is to "efficiently acquire back scattered light and fluorescence." C‑CAMP's stated purpose is a low‑cost alternative to bulky flow cytometers ("Low cost, approx Rs. 2‑4 lakhs as compared to the flow cytometer costing 50‑100 lakhs"; "detect fluorescence signal from even single cell"). Cost reduction and signal efficiency are ordinary design incentives; recovering already‑paid‑for excitation photons instead of adding a second laser directly serves them.
• C‑CAMP's own downstream second fibre pair demonstrates that the artisan already contemplates two detection events on the same cell within a single, short flow channel and treats them as addressable by one microcontroller — the architectural pre‑condition for the claimed arrangement.

Rationale 3 — The technique of routing separated light back into the optical path is a known technique in optical circuits, represented in the record by JPH1187823A (KDD) — subject to the verification caveat in §2.3 above. Used this way, the reference supplies only the general, pre‑existing technique of feeding wavelength‑separated light back through the optical path (loop/circulator/selective‑reflector practice). Its combination with particle‑analysis optics would be a routine transfer of a known technique to a new but analogous field, with predictable results.

Rationale 4 — The patent's own characterization of the problem supplies the stated motivation, though it must be treated with care: the specification states, "there has been a demand for increasing the utilization efficiency of the excitation light not irradiating the fine particle flowing in the flow passage," and describes the excitation light not striking the cell as retaining its characteristics "at a considerably high level" after the objective lens. That is the applicant's own admission that (i) the problem of wasted excitation light was recognized and (ii) the recovered excitation light remains usable as an illumination beam. Under In re practice, an applicant's admission about the state of the art and about the behavior of the un‑consumed light is evidence bearing on the POSA's expectations. The examiner can pair this with Sony '650's own efficiency objective to state an articulated motivation without resorting to the applicant's disclosed solution.

5. Ground of rejection #2 (alternative): Sony '650 alone + C‑CAMP, on the "obvious to try / finite number of identified solutions" rationale

Even without JPH1187823A, a rejection can be framed as: given a first station that separates excitation from fluorescence in an optical fiber (Sony '650), and a second, downstream fibre‑coupled station in the same channel (C‑CAMP), the artisan has only two identified options for energizing the second station — (i) provide another laser, as C‑CAMP does, or (ii) reuse the excitation light already routed into the fiber by the first station. Option (ii) requires no new apparatus beyond an optical coupling between the first separation portion's excitation output and the second excitation waveguide — the very coupling Sony '650 already teaches for its filtered output ("light transmitted through the optical filter is received by the optical fiber") and that C‑CAMP already teaches in the opposite direction (fibre‑coupled laser sources feeding exciting optical channels). Expected benefit: signal from the same cell at two spots without a second source. Expected cost: none beyond an extra fiber run. That is the KSR "predictable variation" case.

6. Dependent claims 2–13 — where the art is strongest and where it is thinnest

7. Counter‑arguments the patentee will raise, and how they fare

1. "The art teaches away — it discards the excitation light." Sony '650's first filter area blocks reflected/unnecessary light; C‑CAMP's F2 uses an FBG to filter out the laser light. But blocking/filtering light at a detector port is not a teaching that the light is worthless as illumination; the references are silent on what is done with the rejected light, which is precisely the classic "silence is not teaching away" posture.
2. "No reference of record discloses recycling, so the combination is hindsight." This is the strongest defense. A well‑supported office action would need either (a) explicit supporting passages in JPH1187823A (unverified here) or another reference showing recovery/re‑use of separated light, or (b) a strong articulated motivation resting on the references' own statements of purpose (Sony '650's "efficiently acquires…"; C‑CAMP's cost and single‑cell sensitivity objectives) plus the admitted, unrecognized problem of wasted excitation light. Ground #2 above is the more defensible of the two on this record.
3. "The recovered excitation light cannot be re‑focused / has degraded characteristics." The specification itself answers this against the patentee: it states the un‑irradiated excitation light "undergoes little change in the polarization direction or the like and maintains characteristics … at a considerably high level," and that only 150–300 ps elapse before the second station. Those are the patentee's own statements about what the POSA would expect — an admission usable against the claim.
4. Secondary considerations. Nothing in the record evidences unexpected results, long‑felt need, failure of others, or industry praise. The asserted benefits (effective doubling of signal, improved S/N, ability to use a lower‑power laser) are the expected consequence of delivering more excitation photons to the particle, i.e., the predictable result of the combination — which supports, rather than defeats, obviousness.

8. Bottom line

• §102: Not available on this record. None of US 2012/0018650 A1, WO 2013/114333 A1, or JPH1187823A discloses all of elements (a)–(f); specifically, none discloses element (d), the re‑radiation of excitation light recovered by the first separation portion.
• §103 — claim 1: Reasonably rejectable over Sony US 2012/0018650 A1 in view of C‑CAMP WO 2013/114333 A1, with or without JPH1187823A. The motivation is supplied by (i) the shared field and shared efficiency/cost objectives of the two primary references, (ii) C‑CAMP's own teaching of two downstream‑spaced, fibre‑coupled detection locations on one channel with in‑fibre filtering and common processing of the same cell, and (iii) the ordinary design incentive to avoid the cost and bulk of a second laser by reusing excitation light already routed into the waveguide — a known technique in optical circuits (JPH1187823A, pending verification of its disclosure text).
• §103 — claims 2–9 and 11–12: Strongest rejections; the elements are either disclosed or are economies/adjacencies the references themselves motivate.
• §103 — claims 5–7 (split fluorescent outputs, dissimilar detectors): Moderate; wants a secondary reference for waveguide‑level splitting of fluorescence, though the dissimilar‑detector selection is well supported by C‑CAMP's list of detector types and the patent's own admitted trade‑offs.
• §103 — claims 10 and 13 (integrated optical fiber ribbon): Weakest on the present record; the three cited references do not disclose a ribbonized fiber, and a rejection would need an additional reference or evidence of conventionality.

Caveats I want on the record: (i) I could not obtain the specification of JPH1187823A; the bibliographic data above is verified, and everything beyond it is expressly characterized as inference from the assignee's contemporaneous work in a different KDD document. (ii) The correspondence of US 8,466,435 B2 to US 2012/0018650 A1 is based on a search hit for the same title/assignee and is not independently verified. (iii) Whether a given claim would in fact be rejected depends on the examiner's identification of specific supporting passages, which is the standard the above analysis is written to.