US 11162819

I'll verify this patent against live sources, including USPTO records and any 2026 CAFC/litigation activity.

Let me do a couple more targeted checks for litigation/PTAB activity and assignee confirmation.

Search results summary — US 11,162,819

Scope note: I searched for the exact number "11162819" against USPTO-derived sources, Google Patents, and Federal Circuit/docket-oriented queries. I found no CAFC 2026 docket, appeal, or PTAB proceeding referencing this patent. I also found no district-court litigation naming it. Any statement below about litigation is therefore a negative finding, not a positive confirmation that none exists.

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Bibliographic data (per Google Patents / USPTO record)

Assignee / ownership — flagging a discrepancy

• Google Patents lists the current assignee as Individual and shows no corporate assignment-in.
• However, the Google Patents legal-events table includes a 2026-04-29 reassignment to BYLINE BANK, AS AGENT — SECURITY INTEREST, Assignors: PANGOLIN LASER SYSTEMS, LLC. Third-party patent-owner databases (ipqwery/OnScope) list the patent under Pangolin Laser Systems, LLC, consistent with the security-interest record.
• Interpretation: the record suggests the patent has moved from the individual inventor to Pangolin Laser Systems, LLC, which in April 2026 granted a security interest to Byline Bank. I could not confirm a recorded assignment from Benner to Pangolin in the sources retrieved, so treat the chain of title as uncertain and verify via the USPTO Assignment database (assignment.uspto.gov) if this matters.

Abstract (verbatim from the patent record)

"A rotary position detector includes a housing having an inner space having a reflective element. A light source emits light rays into the inner space. A base supports a light detector assembly having a first number of toroidal-sector-shaped light sensors arranged circumferentially about a motor shaft axis, i.e., one 'Cosine +' detector element, one 'Cosine −' detector element, one 'Sine +' detector element, and one 'Sine −' detector element. A light blocker positioned between the light source and the light sensors rotates with the shaft. The light blocker includes a second number of opaque, equal-surface-area elements arrayed about the axis, the second number equal to one-half the first number. A circuit measures a signal from the detectors relating to an amount of light falling thereon, a difference related to an angular position of the motor shaft."

Analytical flag: the abstract's "reflective element" and "a second number of opaque, equal-surface-area elements … equal to one-half the first number" do not appear in the granted independent claims (which recite a single opaque element). This language appears carried over from the related galvo-detector family (e.g., US 8,508,726 / US 7,940,380 lineage). It is an abstract/claim mismatch worth noting for any claim-construction or family analysis.

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Plain-language overview of the independent claims

Claim 1 — rotary position detector (apparatus). A detector with:

1. a housing with an inner space;
2. a shaft entering that space and rotating about an axis;
3. a light source emitting light into the space;
4. a light detector inside the space, spaced from the source, having four segmented light sensors around the axis — exactly one "Cosine +", one "Cosine −", one "Sine +", and one "Sine −" element;
5. a light blocker between the detector and the source, comprising an opaque element that rotates with the shaft (the shadow-casting part); and
6. a signal connection for measuring the light falling on the sensors so the absolute rotary position of the shaft can be measured.

The inventive core: a low-inertia, four-quadrant sine/cosine shadow-cast optical detector whose proportional (sin/cos) readout yields absolute 360° position, avoiding the limited ~50° range of prior galvo detectors and the inertia of resolvers/magnets.

Claim 20 — method for determining rotary position. Steps:

1. transmit light into the inner space of a housing having a shaft;
2. detect light with a detector having one each of "Cosine +", "Cosine −", "Sine +", "Sine −" elements;
3. digitize the Cosine output (from the Cosine + / Cosine − pair);
4. digitize the Sine output (from the Sine + / Sine − pair); and
5. call atan2(Sine, Cosine) to derive the sensor angle.

Selected dependent claims (for context, not exhaustive): sensors in a plane parallel (cl. 2) or perpendicular (cl. 3) to the axis; arcuate/toroidal sector shapes (cl. 4–5); rectangular receiving surfaces (cl. 6); blocker radial extent less than the sensors (cl. 7); unitary on-axis light source (cl. 8); an included motor (cl. 13); anti-parallel Cosine pair with a single amplifier (cl. 14–15); anti-parallel Sine pair with amplifier (cl. 16–17); and separate per-element amplifiers summed by a third amplifier (cl. 18–19). Claim 21 adds table-based linearization: compute a correction table, compare the atan2-derived angle to it, apply the correction, output a corrected absolute angle.

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Prior art cited on the face of the patent (6 references)

US 2006/0118707 A1 (Schaake); US 2004/0227065 A1 (Thorburn); US 2011/0101209 A1 (Benner — same inventor's earlier family member); WO 2010/130801 A1 (CSEM); US 8,809,763 B1 (Lincoln Laser); US 2016/0084677 A1 (Scanlab). Non-patent citation: International Search Report dated Oct. 17, 2018 for PCT/US18/44624.

Forward citations

Two Alcon Inc. publications cite this patent: US 2024/0325093 A1 and US 12,569,304 B2 (both priority 2020-08-28, "Optical coherence tomography guided robotic ophthalmic procedures"), indicating use/awareness in ophthalmic robotic OCT contexts.

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Points of uncertainty (explicit)

1. No CAFC 2026 or PTAB activity located for US 11,162,819 — I could not positively verify a docket; absence of results is not proof of no activity.
2. Assignee ambiguity: Google Patents says "Individual"; the April 2026 security-interest record and third-party databases point to Pangolin Laser Systems, LLC. The exact assignment chain (inventor → company) was not confirmed in retrieved sources.
3. Abstract/claim mismatch (reflective element; "second number … equal to one-half the first number") noted above — verify against the granted specification before relying on the abstract.
4. I could not independently retrieve the USPTO PatentCenter/Assignment pages directly in these searches; the bibliographic data above is drawn from the Google Patents record (which mirrors USPTO data) plus third-party owner databases, so confirm against PatentCenter for anything legally operative.

If you want, I can next pull the patent's full prosecution history (file wrapper) or run a dedicated PACER/CAFC docket query on the parties (Benner / Pangolin Laser Systems) to close out the litigation question.

I'll search for litigation involving US patent 11162819 across patent litigation databases.

Let me search dedicated litigation databases.

Let me search additional targeted litigation sources.

Litigation Search Results — US Patent 11,162,819

Bottom Line

Based on my searches, I found no record of any litigation involving US Patent 11,162,819 — no district court infringement action, no declaratory judgment action, no ITC Section 337 investigation, and no CAFC appeal in which the '819 patent is the (or a) patent-in-suit.

I want to be explicit about the limits of this conclusion: I could not access fee-based litigation databases (Docket Navigator, Lex Machina, RPX Insight) directly, and my CourtListener/PACER-oriented searches were cut short by tool limits. So my conclusion rests on the public sources I was able to reach, not an exhaustive database sweep.

What I searched and what came back

• Queries for "11162819" + litigation/lawsuit/complaint/defendant returned no case naming the '819 patent. Results that contained the string "11162819" were unrelated (e.g., a UK Companies House gazette number list, a PubMed ID [11162819] for a varicella-zoster virus paper, and an unrelated EP patent PDF).
• Case-law results that surfaced were the well-known Rule 19 / indispensable-party cases (STC.UNM, Dainippon, Loral Fairchild) and unrelated appeals such as VL Collective IP, LLC v. Unified Patents, LLC (Fed. Cir. 24-1890) — none involve the '819 patent.
• Owner-targeted searches (Pangolin Laser Systems, William R. Benner, Jr.) surfaced the patent's IP ownership records but no suit.

Relevant facts about the patent (from the authoritative full text)

• Patent: US 11,162,819 B2, "Low inertia rotary position detector and associated methods"
• Inventor: William R. Benner, Jr.
• Application: US 16/635,659 (PCT/US2018/044624; WO2019028038A1)
• Priority: 2017-07-31; Filed: 2018-07-31; Granted: 2021-11-02
• Status: Active, adjusted expiration 2038-10-30

Key distinction — not litigation. The Google Patents legal-events record shows a 2026-04-29 assignment of a SECURITY INTEREST to BYLINE BANK, AS AGENT, assignor PANGOLIN LASER SYSTEMS, LLC. This is a security-interest filing (collateralizing the patent), not a lawsuit. Note this appears in the record even though the record also lists the "current assignee" as "Individual"; a third-party ownership database (IPQwery) lists Pangolin Laser Systems, LLC as owner.

Also not litigation. The "Cited By" entries — US 2024/0325093 A1 and US 12,569,304 B2, both assigned to Alcon Inc. (priority 2020-08-28) — are later patents that cite the '819 patent as prior art. A forward citation is not an infringement suit.

Caveat on the "no litigation" finding

A nil result here means "no publicly indexed litigation was found in the sources I could reach," not a certified negative. To confirm definitively, the following should be checked directly (I was unable to complete these):

• Unified Patents litigation portal (portal.unifiedpatents.com/litigation/caselist)
• CourtListener RECAP docket search restricted to the exact string "11162819"
• PACER for any district court filing asserting the '819 patent
• USPTO Patent Center / Assignment records and the ITC EDIS system

If you can provide access to a specific database or confirm the patent owner entity, I can run a narrower docket query.

I'll verify the "no PTAB activity" default against public sources before reporting.

Let me run a few targeted checks on dockets and PTAB-facing sources.

Proceedings overview

Total AIA trial proceedings on file for US 11162819: 0. The USPTO Open Data Portal (ODP) returns no IPR, PGR, or CBM proceedings for this patent as of the most recent ingest, and targeted web searches of PTAB-facing sources surfaced no petition, institution decision, Final Written Decision, or appeal tied to patent number 11,162,819 or to its WO counterpart WO2019028038A1. Breakdown by status is therefore: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0.

The defensive posture this gives a defendant is the opposite of a hardened patent: all 21 claims stand exactly as issued, untested and un-narrowed, with zero PTAB record, zero petitioner estoppel, and zero institution precedent to work around. That is a double-edged sword — the patent owner cannot point to any PTAB victory, but a defendant also has no existing FWD to lean on and must build a validity challenge from scratch. Practically, this is a "clean-slate, first-mover" situation rather than a "the patent has survived and is hardened" situation.

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Proceedings

None — no AIA trial proceeding has been filed against US 11162819

• Type: n/a
• Filed: n/a
• Status: n/a (no proceeding on file; no petition number exists to report)
• Judge panel: n/a
• Petition grounds: n/a
• Institution decision: n/a
• Final Written Decision: n/a
• Settlement / termination: n/a
• Appeal: n/a
• Defensive value: Because there is no FWD, no claim of this patent has been canceled, and no claim has been sustained either. A defendant cannot argue "claims 1–5 are dead." The only validity weapon currently available is a fresh petition.

Sources checked / verifiable anchors: structured ODP "PTAB proceedings on file" block (canonical, negative); Google Patents file wrapper for US11162819B2 (no PTAB trial documents); PTAB E2E search surface ptacts.uspto.gov; PTAB decisions library uspto.gov/patents/ptab/decisions; Federal Circuit / CourtListener search for the patent number (no hits).

I could not complete every verification query I intended, so I state the limit plainly: I found no PTAB proceeding, but this is a negative finding from public sources, not a certified absence. Any defendant should re-run the E2E docket by patent number and by assignee before relying on it — a recently filed petition can lag ODP ingest by weeks.

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Context worth knowing (not PTAB proceedings, but they shape the picture)

• Ownership/RPI wrinkle. Google Patents lists the original assignee as "Individual" (inventor William R. Benner, Jr.) and a recorded security interest dated 2026-04-29 in favor of BYLINE BANK, AS AGENT, assignor PANGOLIN LASER SYSTEMS, LLC. Commercial entities in this family (Pangolin Laser Systems) appear on sibling patents (e.g., US10955266B2, US10539433B2, US10734857B2). Before filing anything, nail down the current titleholder and the correct real party in interest — a misnamed RPI is a routine way to lose a petition.
• Related, previously-litigated family art. The specification expressly cites Benner's own earlier galvo sensors — US 7,688,432, US 7,940,380, US 8,508,726 — and admits they "can only be used over a limited rotation angle—typically 50 degrees or less." That admission is the obviousness fulcrum for a 360°-capable claim set.
• Prosecution-cited references. The face of the patent lists US2004/0227065A1 (Thorburn), US2006/0118707A1 (Schaake), WO2010130801A1 (CSEM), US2011/0101209A1 (Benner), US8809763B1 (Lincoln Laser), and US2016/0084677A1 (Scanlab). Anything among these that the examiner already considered invites a § 325(d) discretionary-denial fight; art outside this list does not.
• Lifecycle dates. Priority 2017-07-31; filed 2018-07-31; granted 2021-11-02; adjusted expiration 2038-10-30; 4th-year maintenance fee paid 2025-04-16; status Active. The patent has a long runway, so there is real incentive to attack it rather than wait it out.

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Strategic summary

Claim status: nothing canceled, nothing sustained, everything untested. US 11162819 issued with 21 claims — independent claims 1 and 20, plus dependent claims 2–19 and 21. If asserted today, claims 1–21 are all live and carry their full original scope. No PTAB panel has construed a single term, no claim has been amended by a contingent motion to amend, and there is no certificate of cancellation or disclaimer of record. Contrast this with a patent that has been through two IPRs: there, a defendant gets free claim constructions and a roadmap of what the Board did and did not buy. Here there is no roadmap — which means both more work and more upside for a defendant.

Estoppel landscape: essentially empty. Section 315(e)(2) estoppel attaches only to a petitioner (and its privies) in an IPR that was instituted and reached a final written decision. With no proceeding on file, no party is estopped from anything, and no prior-art ground has been "used up." Three timing traps still matter for a defendant: (1) § 315(b) — a petition is time-barred if filed more than one year after service of a complaint alleging infringement; if you have been sued, count the days from service, not from the demand letter; (2) § 315(a)(1) — a petition is barred if you first filed a civil action challenging validity (declaratory judgment), so sequence your DJ and IPR filings deliberately; (3) § 325(d) — ground selection should be steered away from the six references already on the face of the patent unless you can affirmatively show the examiner never reached their substance, or that some other Becton Dickinson factor favors you.

Pattern signals: none, which itself is the signal. There is no serial petitioner, no Unified Patents-style defensive aggregator in the chain, and no patent-owner PTAB appellate activity to characterize, because there is no PTAB activity at all. A 2017-priority optical position sensor that has never drawn a single IPR tends to mean one of two things: the patent has not been aggressively asserted (so no target has had the § 315(b) clock and the commercial motive to file), or it has been asserted in low-stakes/individual-defendant matters where nobody funded a petition. Either way, the first well-funded defendant to move faces no discretionary-denial baggage from prior panels and can shape the first construction of the key terms — "segmented light sensors," "opaque element rotatable with the shaft," and the functional "absolute rotary position" language of claim 1.

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Recommended next steps

• No PTAB proceeding exists to link to. I will not manufacture a proceeding number, a panel, or a disposition. There is no Final Written Decision for this patent to cite, and there is no Federal Circuit appeal to cite. Do not represent otherwise in any brief, opinion, or demand-response letter.
• If you are a defendant and are weighing an IPR: this is a genuinely unburdened petition. Confirm no earlier-served complaint has started your § 315(b) one-year clock, confirm you have not filed a DJ of invalidity first (§ 315(a)(1)), and budget for a § 325(d) fight on the six prosecution-cited references. The strongest ground candidates are the applicant's own admitted prior art in the specification — US 7,688,432, US 7,940,380, and US 8,508,726 — combined against independent claims 1 and 20.
• Trial-stage milestones: not applicable, because no trial is pending. If a petition is filed, the statutory clock is fixed: institution decision due within 6 months of the petition's filing (35 U.S.C. § 314(b)) and a Final Written Decision due within 12 months of institution (§ 316(a)(11), extendable up to 6 months for good cause). A defendant weighing a stay request should map the projected FWD date against the district court's trial date before filing, given the Board's current § 314(a) discretionary-denial practice.
• Verify before relying. Re-query PTAB E2E by patent number and by assignee, and check the assignment record for the current owner and any exclusive licensee. The negative finding here is from public sources on 2026-09-29 and carries the usual ingest lag risk.

I'll research this patent's ownership chain across USPTO assignment records and related sources.

Scope note: I retrieved assignment data from the Google Patents legal-events feed embedded in the authoritative full text you provided, plus Justia / PatentGuru / onScope assignee records, Florida Division of Corporations filings, and a Byline Bank press release. I could not complete a live, interactive query of assignmentcenter.uspto.gov, so I do not have reel/frame numbers or the recorded correspondent for the single post-issuance event. I flag every place where that gap matters rather than filling it in.

Inventors

Unusual-pattern check — negative. There is no multi-inventor team here, so the classic "all inventors departed the assignee within 12 months of filing" fire-sale precursor cannot occur. The opposite pattern is present: a single founder-inventor who has filed under the same corporate umbrella continuously from 2005 (WO2006096156) through 2019 (US10955266). That is a long-tenure operating-company inventor signature, not a churned portfolio.

One anomaly worth logging: the PCT (WO2019028038A1) and the resulting US national-phase application name "Benner Jr William R" as the applicant, not Pangolin Laser Systems, Inc. Every sibling Pangolin patent (US10539433, US10955266, US10734857) names Pangolin Laser Systems, Inc. as assignee. So this patent issued to an individual rather than to the operating company — see the next section.

Original assignee

• Named on the issued patent: "Individual" (Google Patents "Original Assignee" / "Current Assignee" fields both read Individual; the WO applicant of record is "Benner Jr William R"). In practical terms: William R. Benner, Jr., personally, not Pangolin Laser Systems, Inc.
• The entity that commercializes the claims: Pangolin Laser Systems, Inc. (now Pangolin Laser Systems, LLC). Founded 1986, headquartered in Sanford/Longwood, FL. Primary line of business: laser control software and hardware for the entertainment industry — laser show controllers, complete laser projection systems, and proprietary design software, plus galvanometer-based optical scanners (the exact field of this patent; the specification's FIG. 1 galvo detector and the "0.35 inch outer diameter" light blocker are shipping-product dimensions, and the patent states detectors "have been manufactured, based on the teachings of this invention" at 16-bit resolution). It ships product embodying the claims.
• Current status: Operating. In 2026, Artistry In Motion, LLC (portfolio company of Emko Capital), in partnership with Graham Sports & Entertainment Partners, merged with Pangolin Laser Systems, LLC, with senior secured financing from Byline Sponsor Finance, a division of Byline Bank (Byline Bank press release: "Byline Sponsor Finance Supports Emko Capital and Graham Sports & Entertainment Partners' Special Effects and Entertainment Platform, a merging of Artistry In Motion and Pangolin Laser Systems"). The corporate form changed from Inc. to LLC between the 2024 Florida annual report and the 2026 recording. This is a private-equity recapitalization, not a bankruptcy or wind-down.
• Inbound (not outbound) IP behavior: Pangolin acquired the intellectual property of Phoenix Showcontroller GmbH & Co. KG in April 2013. Pangolin is a net IP buyer, which is an operating-company tell.

Assignment timeline

Important limitation: the USPTO Assignment Center returned no ownership-transfer record I was able to retrieve for US 11162819. The only post-issuance recorded event surfaced anywhere is a security interest, and its reel/frame and correspondent were not retrievable from the sources I could reach. I will not invent them.

• 2026-04-29 (recorded; execution date not exposed in the feed) — Reel NNNNNN/NNNN (not retrievable)

  • Conveyance: Security Agreement / Security Interest (Google Patents legal-event code "reassignment," conveyance text "SECURITY INTEREST")
  • Assignor: PANGOLIN LASER SYSTEMS, LLC
  • Assignee: BYLINE BANK, AS AGENT
  • Correspondent: not retrievable — the Google Patents legal-event feed does not carry the correspondent of record, and I could not complete a live Assignment Center query. I cannot make the repeat-correspondent call for this chain. For context (not a finding): the sibling Pangolin patents list prosecution agencies GrayRobinson, P.A. (US10734857) and Greenberg Traurig, P.A. (US10955266) — both full-service general-practice firms, which is an operating-company profile rather than the boutique-recorder profile typical of NPE portfolio filings.
  • Context: securitization — a lender's blanket security interest in the borrower's IP collateral, taken as part of the Byline Sponsor Finance-funded AIM/Pangolin combination. It is a lien, not a transfer of title; ownership remained with the Pangolin entity.

• No recorded assignment from William R. Benner, Jr. to Pangolin Laser Systems, Inc./LLC appears in the Google Patents legal-events feed. This is a real gap with two possible explanations, and I cannot distinguish them on the available record: (i) an assignment was executed but never recorded, or (ii) Google's legal-events feed is incomplete for this patent. Either way, it is corroborated indirectly that the Pangolin entity held rights in the collateral: a grantor must have rights in the collateral to grant a security interest in it, so Pangolin Laser Systems, LLC held rights in US 11162819 as of 2026-04-29.

Other date anchors (not assignments): provisional 62/539,257 filed 2017-07-31; PCT/US2018/044624 filed 2018-07-31; US national phase US16/635,659 filed 2018-07-31 and published as US20200363239A1 on 2020-11-19; patent granted 2021-11-02; 4th-year maintenance fee paid 2025-04-16; adjusted expiration 2038-10-30.

Timeline diagram

timeline
    title Ownership of US 11162819
    2017 : Provisional filed by William Benner Jr
    2018 : PCT filed with Benner as applicant
    2020 : US national phase published
    2021 : Patent issued to individual owner
    2025 : Fourth year maintenance fee paid
    2026 : Pangolin Laser Systems LLC grants
         : security interest to Byline Bank

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No assignment to any "IP / Patents / Licensing / Holdings / Ventures" entity appears anywhere in the record. The only recorded instrument is the 2026-04-29 security interest, in which the grantor is the operating company itself (Pangolin Laser Systems, LLC) and the secured party is a chartered commercial bank (Byline Bank, parent Byline Bancorp, Inc.). A bank taking collateral is the opposite of a shell-entity transfer.

2. Known asserter in the chain — not present. No assignee in the chain matches any of the listed NPE families (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). Assignees of record are (a) an individual inventor and (b) BYLINE BANK, AS AGENT — a bank, per record. The other principals in the 2026 transaction (Emko Capital, Graham Sports & Entertainment Partners) are private-equity and sports/entertainment investors, not known asserters. I found no assertion by any entity against US 11162819.

3. Repeat correspondent across the chain — unclear / not assessable. There is effectively a one-link chain, so recurrence cannot be tested within this patent. I could not retrieve the correspondent of record for the 2026-04-29 entry, and I will not attribute a firm to it. For reference only: sibling Pangolin patents use GrayRobinson, P.A. and Greenberg Traurig, P.A. — general-practice firms used by operating companies.

4. Cascading transfers — not present. Exactly one recorded event, and it is not a transfer of title. No chained LLCs within any time window.

5. Pre-litigation transfer — not present. No infringement suit naming US 11162819 was found. The only forward citations are to Alcon Inc. (US20240325093A1 and US12569304B2, "Optical coherence tomography guided robotic ophthalmic procedures," priority 2020-08-28) — these are third-party citations of this patent, i.e., Alcon built on the disclosure. A citation is not an assertion, and Alcon is not in the ownership chain.

6. Bankruptcy fire-sale — not present. The 2026 Pangolin event is a growth recapitalization and merger, not a Chapter 7/11 disposition. Byline Sponsor Finance's own description is a platform combination, and Byline Bancorp's subsequent 8-K includes Item 2.03 (creation of a direct financial obligation) — a new financing, not a liquidation. No bankruptcy docket surfaced for Benner or Pangolin.

7. Privateering — not present. No operating company transferred this patent to an NPE to assert against competitors. The patent sits with (or under lien from) the founder and his own operating company.

8. Defensive aggregator (anti-NPE) — not present. Chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN.

Cross-check note: I also examined the six references cited on the face of the patent and the six later-citing documents. None of the cited prior art (Thorburn US20040227065A1, Henk Schaake US20060118707A1 "Optical controls," CSEM WO2010130801A1, Lincoln Laser US8809763B1, Scanlab US20160084677A1) or the family references (Benner's own US7688432 / US7940380 / US8508726 and US20110101209A1) is an ownership-chain participant. They are prior-art citations only and carry no assignment weight.

Verdict

Insufficient data.

The honest reason is structural, not evidential weakness: there is no recorded ownership transfer of US 11162819 at all. The only post-issuance instrument surfaced anywhere is the 2026-04-29 security interest from PANGOLIN LASER SYSTEMS, LLC to BYLINE BANK, AS AGENT, which is a lien granted by the operating company to its lender — not a transfer of title — and for which I could not retrieve the reel/frame or correspondent. Every affirmative signal therefore points away from an NPE: the chain terminates at the original founder-inventor and his own operating company, which ships galvo/laser-entertainment hardware embodying the claims, has never sued on this patent, and whose 2026 event is a PE-backed merger (Emko Capital / Graham Sports & Entertainment) rather than a shell transfer or fire-sale. The one open item that could change this call is the apparent unrecorded assignment from Benner to the Pangolin entity — if such an assignment were later recorded, this would resolve to an ordinary operating-company chain; it would not, on this evidence, support an NPE classification.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 11162819) or https://assignment.uspto.gov/patent/index.html — specifically request the reel/frame and correspondent of record for the 2026-04-29 "SECURITY INTEREST" entry, and ask whether any Benner → Pangolin Laser Systems, Inc. assignment is recorded.

I'll research US Patent 11162819 and its cited prior art. Let me begin with searches to verify the patent and gather citation details.

Let me research each cited prior-art reference in detail.

Prior-Art Analysis — US Patent 11,162,819 B2

Patent under review: US 11,162,819 B2 — "Low inertia rotary position detector and associated methods"

• Application No. US 16/635,659; PCT/US2018/044624 (WO 2019028038 A1)
• Inventor: William R. Benner, Jr.; originally assigned to an individual (later PANGOLIN LASER SYSTEMS, LLC / security interest to Byline Bank, per the assignment record dated 2026-04-29)
• Priority date: 2017-07-31 (provisional 62/539,257); filed 2018-07-31; granted 2021-11-02
• Status: Active, adjusted expiration 2038-10-30

Note on method: The USPTO/Google Patents record for US 11,162,819 lists exactly six (6) patent citations and one non-patent citation (the ISR). I did not locate any additional USPTO "References Cited" beyond these in the available record; where I could not independently verify a full claim-by-claim mapping I say so explicitly rather than infer it.

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Statutory timing

All six cited documents have publication dates between 2004 and 2016 — i.e., all predate the 2017-07-31 priority date and are therefore available as prior art under at least 35 U.S.C. § 102(a)(1)/(a)(2) (pre-AIA § 102(a)/(b)). Two of them (marked with an asterisk in the record, indicating examiner-cited art) are US 2006/0118707 A1 and US 2016/0084677 A1.

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The cited references

1. US 2004/0227065 A1 — Thorburn, William G.

• Title: "Rotary position sensor with offset beam generating element and elliptical detector array"
• Assignee: MicroE Systems Corp.
• Filing/priority: Filed 2003-12-16 (PCT/US2003/040235); priority US provisional 60/433,828, 2002-12-16. Published: 2004-11-18. (Also issued as US 7,183,537 B2; published as WO 2004/059346 A3.)
• Description: An absolute rotary position sensor using an offset beam-forming element (a tilted mirror or a reflective diffraction grating) attached to the rotating member. Light from a source is reflected/diffracted into one or more spots that trace a generally elliptical/annular path on a segmented detector array (two, four, or more regions; also annular, quadrant, and CCD arrays). The azimuthal position of the spot around the annular path gives the rotation angle; a differential "searchlight" beam pair can be used, and the detector is divided into multiple regions so a processor can identify the azimuthal angle. Specifically contemplates a custom detector that is photosensitive only in an annular region around the source and divided into four or more segments to track the beams; also supports four-segment (quadrant) detection.
• Potential § 102 relevance: Because it discloses four-or-more-segment annular detectors and a processor resolving an absolute angle over 360°, it is the closest structural analogue to independent claim 1 (four circumferentially arranged light sensors + light source + signal connection resolving an absolute rotary position) and to dependent claims 4 and 5 (arcuate/toroidal-sector detector elements). However, its angle encoding relies on beam reflection/diffraction geometry, not on a rotating opaque light blocker interposed between source and detector — so it does not appear to anticipate the "light blocker … comprising an opaque element rotatable with the shaft" limitation of claim 1. Treat as § 102-anticipatory only for a sub-combination (segmented 360° annular detector array); most likely § 103 art against claims 1, 4, 5.

2. US 2006/0118707 A1 — Schaake, Henk (examiner-cited, *)

• Title: "Optical controls"
• Assignee: Cliff Plastic Products Ltd. / Digicliff Limited
• Filing/priority: PCT/GB2003/001524 filed 2003-04-08; priority GB 0208048.9, 2002-04-08. US national phase 10/510,376; published 2006-06-08. (Corresponding GB 2390424 B; WO 2003/087729 A3.)
• Description: Optical switches/encoders in which a reflector redirects and concentrates light from one or more LEDs onto one or more photodetector locations, allowing a more compact, face-away optical arrangement; also discusses blocking/attenuating light to a detector in analogue and digital optical controls.
• Potential § 102 relevance: Its disclosure is directed to optical control construction (reflector-based light routing) rather than to a four-quadrant sine/cosine absolute shaft encoder. It does not disclose the four Cosine±/Sine± detector elements or an atan2-based absolute angle solution. Unlikely to anticipate any claim; its examiner citation is best explained as § 103 background art on optical light-routing/blocking arrangements. I could not verify a specific claim it anticipates, and I decline to assert one.

3. WO 2010/130801 A1 — CSEM Centre Suisse d'Electronique et de Microtechnique SA

• Title: "Device and method for measuring an absolute angular position"
• Filing: 2009-05-13; published 2010-11-18. (Family: EP 2251647 A1; EP 2430403 A1.)
• Description: An absolute optical angular-position device/method that images a mask (repetitive two-dimensional pattern of transparent/opaque areas) onto an image sensor and processes the shadow image to compute absolute angular position to nanometric resolution. Related CSEM work ("Nanometric resolution absolute position encoders," Masa et al., ESMATS 2009) uses shadow-imaging with a code-plate and image sensor.
• Potential § 102 relevance: It discloses optical absolute angular position sensing using a shadow-casting mask between light source and sensor — conceptually close to the "light blocker casting a shadow" concept — but it uses an image sensor with pattern decoding rather than four discrete sine/cosine detector elements and an atan2 computation. It therefore does not appear to anticipate claim 1 (which requires exactly four segmented sensors, one each of Cosine±/Sine±) or claims 20/21 (which require digitized Sine/Cosine outputs and the atan2 function). Best characterized as § 103 art on optical absolute position detection / shadow masks.

4. US 2011/0101209 A1 — Benner, Jr., William R.

• Title: "Rotary position detector and associated methods"
• Filing/priority: Filed 2007-01-23; published 2011-05-05.
• Description: A rotary position detector of the galvanometer ("galvo") type by the same inventor as US 11,162,819. As described in the background of the instant patent itself (and consistent with similar documents US 7,688,432, US 7,940,380, US 8,508,726), this family uses optical intensity sensing on segmented photodetector elements in a compact, low-inertia arrangement, but is limited to a restricted rotation range (typically ~50° or less).
• Potential § 102 relevance: This is the most closely related family member and shares the inventor and much of the optical-detection architecture. However, the instant patent's express point of novelty is extension to full 360° absolute detection with four Cosine±/Sine± elements; the Benner reference is characterized (including by the instant specification) as limited-angle. If the reference discloses the four-element arrangement and the differential sine/cosine signal combination for its limited range, it could be § 102-anticipatory for claims 14–19 (anti-parallel Cosine± / Sine± connection and amplifier configurations) as a sub-combination, but not for the 360° absolute-position limitations of claim 1/20/21. This is the reference I would scrutinize first for § 102/§ 103 against the dependent amplifier-connection claims. Caveat: I have not verified the exact element layout of US 2011/0101209 A1 against each claim, so this mapping is provisional.

5. US 8,809,763 B1 — Lincoln Laser Company

• Title: "Optical position sensor for determining the angular position of a rotating device"
• Filing/priority: Filed 2011-01-20; published/granted 2014-08-19.
• Description: An optical position sensor determining angular position of a rotating device (Lincoln Laser is a galvo/scanner manufacturer). Consistent with that field, it concerns optical detection of a rotating member's angle, likely with low-inertia, segmented/differential photodetection.
• Potential § 102 relevance: Relevant as optical rotary-position-sensing art in the same galvo-adjacent space. Based on the available record I cannot attribute a specific claim of US 11,162,819 that it anticipates; I would classify it as § 103 background art on optical angular position sensing rather than § 102 anticipatory art for the claimed four-element 360° configuration. Flagging my uncertainty explicitly here.

6. US 2016/0084677 A1 — Scanlab Aktiengesellschaft (examiner-cited, *)

• Title: "Optical Angle Detector Having a Beam-Forming Element"
• Filing/priority: Priority 2013-05-10; published 2016-03-24. (Family JP 2016-517963 A mentions "Optical angle detector with beam forming element.")
• Description: An optical angle detector employing a beam-forming element; Scanlab is a laser-scanning/galvo company. This is the same general technical space (optical detection of a scanner/rotating element's angle).
• Potential § 102 relevance: Examiner-cited (asterisked in the record), indicating it was considered material. Its "beam-forming element" optical angle detection and single-opaque-blocker-adjacent architecture make it relevant background art on the claim 1 architecture and the light-blocker concept. As with the Lincoln Laser reference, I cannot from the available record attribute a specific anticipated claim with confidence; treat as § 103 art against the general detector/blocker architecture.

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Non-patent citation

• International Search Report dated Oct. 17, 2018 for PCT/US2018/044624 (the ISR for the parent PCT application). This is a procedural document, not prior art on its own, though the documents it identifies would be the operative art.

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Summary assessment

Conclusion: None of the six cited references, on the record available, discloses every element of independent claim 1 (notably the single opaque, shaft-rotatable light blocker interposed between a light source and exactly four circumpherentially arranged Cosine±/Sine± detectors producing a full-360° absolute position) or of independent claims 20/21 (the digitize-Sine/Cosine-plus-atan2 method and the correction-lookup-table step). The examiner-cited references US 2006/0118707 A1 and US 2016/0084677 A1, and the annular-segmented-detector reference US 2004/0227065 A1, are best understood as the primary § 103 combination art against the claim 1 architecture, and US 2011/0101209 A1 (same inventor) is the reference most likely to bear on the dependent amplifier/anti-parallel-connection claims 14–19.

Important caveats / limits of this analysis:

1. My claim-mapping for US 2011/0101209 A1, US 8,809,763 B1, and US 2016/0084677 A1 is provisional — I was not able to complete a claim-by-claim comparison within the available sources before reaching the research limit.
2. Anticipation under § 102 requires a single reference disclosing each and every claim limitation arranged as in the claim; none of the references above satisfied that test for claims 1, 20, or 21 on the evidence available, so most of these are § 103 (obviousness) references rather than true anticipatory art.
3. If a formal invalidity/FTO opinion is required, the full text (not just the abstract/description excerpts) of US 2004/0227065 A1, US 2011/0101209 A1, and US 2016/0084677 A1 should be obtained and mapped against each of claims 1–21.

I'll research the prior art references cited on this patent's page to ground the obviousness analysis.

Let me get details on the applicant's own earlier patents and the Schaake reference.

Obviousness Analysis — US 11,162,819 B2 under 35 U.S.C. § 103

Patent: US 11,162,819 B2, "Low inertia rotary position detector and associated methods"
Inventor: William R. Benner, Jr.; Appl. 16/635,659 (PCT/US2018/044624; WO2019028038A1)
Priority: 2017‑07‑31; Granted: 2021‑11‑02; Expiration: 2038‑10‑30
Analysis date: April 26, 2026

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1. Legal framework and scope

This is a § 103 analysis using the prior art of record on the patent page (6 patent citations + 1 non‑patent citation + the "Similar Documents" family). I apply KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (predictable combination of known elements; "obvious to try" where the design space is finite and the results predictable) and Graham v. John Deere, 383 U.S. 1 (1966) (scope/content of claims; differences; PHOSITA level; secondary considerations).

Level of ordinary skill. A person having ordinary skill in the art (POSITA) here would be a mechanical/optical or electrical engineer with several years' experience designing electro‑optical position sensors for motors and galvanometer scanners — including the standard "shadow‑cast" detector art and the standard quadrature (sine/cosine) signal‑processing art used in resolvers and optical encoders.

Claim 1 (independent) requires, in substance:

1. housing with an inner space;
2. a shaft rotatable about an axis, extending into the space;
3. a light source emitting into the space;
4. a light detector spaced from the source, comprising four segmented light sensors about the axis, being one "Cosine +", one "Cosine −", one "Sine +", and one "Sine −" element;
5. a light blocker between the detector and the source, comprising an opaque element rotatable with the shaft; and
6. a signal connection to measure light on the sensors to thus measure an absolute rotary position of the shaft.

The claim does not require toroidal geometry (that is claim 4/5), a single blocker element (claim 1 says "an opaque element"), a specific blocker angular subtense, or any particular decoding algorithm (that is method claim 20). Under the broadest reasonable interpretation, the "Sine/Cosine" labels are functional/positional — i.e., four detector segments occupying 90°‑spaced quadrature positions and combined differentially to yield two orthogonal signals.

Note on ownership/status (from prior section): the record shows a security‑interest assignment to BYLINE BANK (2026‑04‑29), assignor Pangolin Laser Systems, LLC, and a third‑party database lists Pangolin as owner, while Google lists "Individual." This affects standing/real‑party issues, not the § 103 merits.

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2. The prior art of record (from the "Prior Art"/Citations section)

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3. The critical differences (what claim 1 actually adds)

Comparing claim 1 to the closest art:

• The Benner family already discloses the entire mechanical/signal architecture of claim 1 — housing, shaft, in‑space light source, circumferentially arranged segmented sensors (including an express four‑sensor embodiment in US 7,940,380 claim 6, and toroidal‑sector sensors in US 8,508,726), a rotatable opaque blocker with half as many elements, radial extent less than the sensors, and an A−B signal connection. What it lacks in claim 1 is (i) the Sine/Cosine labeling/quadrature pairing of exactly four elements, and (ii) the absolute (over 360°) framing.
• Lincoln Laser already discloses four sector‑shaped detector segments with cross‑connected differential summation and a rotating blocker — but for a galvo (relative, limited‑angle) sensor.
• Thorburn and CSEM already disclose absolute angular position over 360° with segmented/partitioned optical detectors — but not the specific low‑inertia four‑quadrant shadow‑cast geometry.
• Scanlab confirms that the four‑ring‑segment photosensor + butterfly blocker + differential amplifier architecture (EP 1 071 929) was known in the same uncoded analog optical‑detector field.

So the asserted advance reduces to: arranging exactly four circumferentially segmented optical sensors as two 90°‑spaced quadrature pairs (Sine and Cosine), with a rotating opaque shadow element, and decoding absolute angle over 360°. Each of these pieces is individually disclosed; the question is whether their combination is non‑obvious. It is not.

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4. Grounds of obviousness

Ground 1 (primary): Benner family + absolute quadrature sensing (Thorburn and/or CSEM)

Combination: US 7,940,380 / US 8,508,726 / US 2011/0101209 (Benner) in view of US 2004/0227065 (Thorburn) and/or WO 2010/130801 (CSEM).

Element mapping. Benner supplies §1–§3, the segmented sensors, the rotatable opaque blocker, the radial‑extent limitation, and the signal‑connection limiation ("structure … the light detector … comprising a first number of segmented light sensors … disposed in pairs about the axis"; "the first number comprises four light sensors," US 7,940,380 cl. 6; "segmented light sensors … in a plane parallel to the axis" / "plane perpendicular to the axis," US 8,508,726 cl. 3, 6). Thorburn supplies the absolute/modus‑360° capability with a detector divided into multiple regions to identify azimuthal angle. CSEM supplies an absolute angular position optical device/method.

Motivation to combine — strong and articulated:

• Same field, same problem. Both Benner and Thorburn/CSEM address measuring the angular position of a rotating shaft. The '819 specification itself frames the problem as: existing low‑inertia galvo detectors (Benner's own) "can only be used over a limited rotation angle — typically 50 degrees or less," while 360° solutions (resolvers, encoders, Hall) suffer high inertia, limited resolution, or high cost. The '819 states there "are not any solutions for applications that require … the entire 360‑degree angular range, and that also offer high resolution, compact size, low cost and low inertia." That is a classic known problem with a known finite set of solutions — the KSR "obvious to try" paradigm.
• Predictable result. Extending a segmented shadow‑cast detector from a limited arc to a full 360° by using four quadrant sensors at 90° intervals and decoding with sine/cosine is a predictable engineering variation, not an unpredictable one. Quadrature sine/cosine sensing is the standard, well‑understood means (resolvers; optical encoders) for obtaining an unambiguous 360° angle via atan2.
• No change in principle of operation. Adding two more segments to a four‑segment layout and pairing diametrically‑opposite ones is a matter of routine circuit/geometry design; nothing about the Benner detector's physics or the Thorburn/CSEM absolute method would be expected to fail.

Reasonable expectation of success: high — the '819 itself admits the output "will be further conditioned and linearized when necessary," and that the decoding is done by a conventional digital servo (atan2 + lookup table). The claimed performance (16‑bit) is a predictable consequence of an analog optical detector with good SNR, not an unpredictable leap.

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Ground 2: Lincoln Laser US 8,809,763 + absolute‑angle art (Thorburn and/or CSEM)

Combination: US 8,809,763 B1 in view of US 2004/0227065 A1 and/or WO 2010/130801 A1.

Element mapping. Lincoln Laser expressly discloses (i) a housing and shaft, (ii) a single light source aligned along the rotation axis, (iii) a "detection element" with "four radially aligned detector segments … four sector‑shaped light detector segments**," (iv) a rotating light blocker between source and detector (butterfly, two blocking segments), and (v) a signal connection that cross‑connects the segments to produce summed outputs (A+D)−(C+B). That is claim 1's structure, with the four segments used as two differentially‑combined pairs. Thorburn/CSEM supply the express absolute, over‑360° result.

Motivation: Same as Ground 1 — to serve brushless‑motor commutation / full‑rotation applications, which require absolute 360° position (the '819's stated use), one of ordinary skill would combine a four‑segment shadow‑cast detector with the known absolute‑angle decoding art. Lincoln Laser's cross‑connection already reduces sensitivity to axial/radial shaft motion — precisely the '819's stated concern.

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Ground 3: Scanlab US 2016/0084677 + the EP 1 071 929 architecture it describes + absolute decoding

Combination: US 2016/0084677 A1 (Scanlab) in view of US 2004/0227065 (Thorburn) and/or WO 2010/130801 (CSEM).

Element mapping. Scanlab's background section describes the analog (uncoded) optical position detector: light falls on a sensor, different regions are covered depending on shaft angle, and output is proportional to illuminated area. It expressly describes EP 1 071 929 B1 as using photo sensors 134, 136, 138, 140 shaped as circular ring segments symmetrically arranged around the rotary shaft, with a "bow tie"/butterfly light‑blocking element 130 connected to the rotary shaft, an LED light source 146, and opposite photo‑sensor signals summed and fed into a differential amplifier. That is effectively the claim‑1 architecture (four ring‑segment sensors about the axis + rotating blocker + differential readout). Adding the Sine/Cosine quadrature pairing and absolute 360° decoding is the same predictable variation as above.

Motivation: The references share the same technical problem — an accurate, compact, low‑inertia, low‑cost optical rotary detector for scanners/motors — and the same "shadow‑cast + differential readout" operating principle. Combining them reflects nothing more than the predictable use of known techniques to improve a similar device in the same way (KSR).

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What about a § 102 anticipation by the applicant's own US 2011/0101209?

Not clean. US 2011/0101209 claim 1 requires (a) a reflective surface within the housing above the blocker, and (b) generically "a first number of … light sensors … in pairs … one 'A' and one 'B' … with the second number [of blocker elements] equal to one half of the first number." The '819 claim 1 instead (i) is transmissive (blocker strictly between source and detector) and (ii) expressly recites one Cosine+/− and one Sine+/− element and absolute position. The four‑sensor species appears only in dependent claims (e.g., US 7,940,380 cl. 6) and is described as A/B, not Sin/Cos. So the better challenge is § 103, not § 102.

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5. Dependent claims

Most dependents are expressly disclosed or plainly obvious over the same art:

• Claim 2 (sensors in a plane parallel to the axis) and claim 3 (plane perpendicular) — verbatim in US 8,508,726 cl. 6 and cl. 3, respectively.
• Claim 4 (arcuate sector shape) / claim 5 (toroidal) — US 8,508,726 cl. 4–5; also the toroidal‑sector sensors of the Benner family.
• Claim 6 (rectangular light‑receiving surface) — US 8,508,726 cl. 7; and the "rectangular light sensor" embodiment of the '819 is itself described as the FIG. 2 variant.
• Claim 7 (blocker radial extent less than sensors) — US 7,940,380 cl. 1/3 ("radial extent of the light blocker elements is substantially less than a radial extent of the light sensors").
• Claim 8 (unitary light source aligned with axis) — US 7,940,380 cl. 5 ("unitary light source generally aligned with the motor shaft axis"); US 8,809,763 ("single light source aligned along the rotation axis").
• Claim 9 (light‑sensor material: more light/area → more output) — US 7,940,380 cl. 7.
• Claim 10 (blocker = blade) — US 7,940,380 cl. 8 ("blades").
• Claim 11 (blocker = transparent tube/disk with opaque elements imposed) — US 7,940,380 cl. 9 ("substantially transparent disk having imposed thereon the opaque elements"); the '819's own spec describes both disk and tube variants.
• Claim 12 (blocker = bottom cylindrical portion of the motor shaft with opening/window) — US 7,940,380 cl. 16 / US 2011/0101209 cl. 16.
• Claim 13 (a motor operable with the shaft) — routine.
• Claims 14–17 (Cosine+/− anti‑parallel + amplifier; Sine+/− anti‑parallel + amplifier) — the differential/anti‑parallel connection of opposed photosensors with a shared amplifier is standard, and is disclosed functionally by Lincoln Laser's cross‑connection ((A+D)−(C+B)) and by EP 1 071 929 as described in Scanlab (opposed sensor signals combined in a differential amplifier).
• Claims 18–19 (individual amplifiers per element, then a combining amplifier) — the alternative connection scheme; the Benner family describes using individual sensor outputs separately, and it is a routine design choice balancing cost/compactness vs. noise.

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6. Method claims 20–21

Claim 20: transmit light; detect with Cos+ / Cos− / Sin+ / Sin− elements; digitize a Cosine output; digitize a Sine output; call atan2(Sine, Cosine) to derive the sensor angle.

Claim 21 adds: compute a table of angle correction values; look up the sensor angle; apply a correction; output the corrected absolute angle.

These steps are textbook quadrature/resolver decoding:

• Digitizing orthogonal sine/cosine channels and computing atan2 is the standard method used by resolver‑to‑digital converters (RDCs) and interpolated optical encoders — well before 2017.
• Thorburn and CSEM both disclose processor‑based determination of the absolute angle from partitioned optical detector signals; the specific atan2 and lookup‑table linearization are the routine implementation of that determination.
• The '819 specification itself concedes the point: it says the device "is particularly useful when connected to a digital servo system, which can digitize the Sine and Cosine outputs … and then perform the Arctangent function along with any linearization afterwards."

A POSITA, given a detector producing orthogonal Sine/Cosine signals (Ground 1–3), would apply this known decoding without inventive effort; the lookup‑table linearization is a conventional means to correct a known non‑linearity (the '819 itself notes the output "will be further conditioned and linearized when necessary"). Claims 20–21 are therefore obvious over any of Grounds 1–3 in further view of the ubiquitous quadrature atan2 decoding art.

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7. Counterarguments and secondary considerations

Potential non‑obviousness arguments the applicant could raise, and their weaknesses:

1. "Unexpected results" — 16‑bit resolution at <0.001 g·cm² inertia in a 0.5″×0.5″ package. Weak as a standalone: the low inertia was already achieved in the applicant's own prior galvo detectors using the same thin‑foil blocker (the '819 spec says the same <0.001 g·cm² figure for the earlier architecture), so the low‑inertia benefit is not attributable to the claimed four‑element Sin/Cos arrangement. High resolution likewise follows predictably from a good‑SNR analog optical detector plus atan2 decoding (and the spec admits the output is linearized in software).
2. "Teaching away" / limited‑angle art. The Benner references are directed to limited‑angle galvo sensors and teach the A/B pair scheme for ramps. But nothing in them (or in Lincoln Laser/Thorburn/CSEM) teaches away from full‑turn quadrature; to the contrary, Thorburn and CSEM explicitly pursue absolute 360° measurement, which supplies the missing motivation rather than a deterrent.
3. "Change in principle of operation." Not available: benner, Lincoln Laser and EP 1 071 929 all operate on the same shadow‑cast + differential‑readout principle as the '819. Adding quadrant pairing and atan2 decoding preserves the principle.
4. Own‑work / common‑ownership. Because US 2011/0101209 published in 2011 (and US 7,940,380 granted 2011‑05‑10), it is § 102(a)(1)/103(a) prior art, and the § 103(c) common‑ownership exception (which applies only to § 102(a)(2) art) does not remove it.

Caveats on my analysis:

• This is a technical, not legal, opinion. A formal invalidity position should also review the prosecution history (esp. whether the applicant overcame these exact references with arguments about the four‑element Sin/Cos arrangement or the absolute‑over‑360° feature), any terminal disclaimers, and the actual claim construction a court would adopt.
• I could not obtain the full text of US 2006/0118707 A1 (Schaake) due to a tool limit, so it is not relied upon. Its inclusion on the face of the patent suggests the examiner treated it as secondary art.
• I have not located any litigation or IPR/PGR on the '819 (consistent with the prior section), so there is no court/PTAB claim‑construction record to anchor the analysis.

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8. Bottom line

Claim 1 is very likely obvious under § 103 over the applicant's own Benner family (US 7,940,380 / US 8,508,726 / US 2011/0101209) — which discloses the entire low‑inertia shadow‑cast architecture, including a four‑sensor embodiment and a rotatable half‑count opaque blocker — in view of absolute‑angle optical sensing art (Thorburn US 2004/0227065 and/or CSEM WO 2010/130801), and further in view of the ubiquitous sine/cosine quadrature technique. Lincoln Laser US 8,809,763 provides an equally strong primary reference (four sector‑shaped segments, cross‑connected differential readout, rotating blocker), as does Scanlab US 2016/0084677 (which candidly describes the four‑ring‑segment + butterfly‑blocker + differential‑amplifier detector of EP 1 071 929). The motivation — extending a known low‑inertia optical sensor to the known goal of absolute 360° measurement for brushless‑motor commutation — is exactly the problem the '819 identifies, and the solution is a predictable combination of known elements with a reasonable expectation of success.

Dependent claims 2–19 are each disclosed or obvious over the same art (many verbatim in US 8,508,726 and US 7,940,380 claims), and method claims 20–21 are obvious over any of the above plus standard atan2/lookup‑table quadrature decoding (a technique the '819 specification itself acknowledges as the conventional digital‑servo implementation).

Confidence: Moderate‑to‑high on the § 103 result for claim 1 and the dependent claims; the limiting factors are (a) my inability to read the full prosecution history and (b) the art's lack of an express "four Sin/Cos elements decoded by atan2 over 360°" teaching in a single reference — which is why the rejection is a combination, not an anticipation.