US 10890543

I'll run several targeted searches for this specific patent number.

Let me check for any litigation or appeal activity involving this patent.

Search scope and sourcing note

I ran targeted searches for the exact string US 10,890,543 / 10890543 across (a) general web/patent aggregators (Google Patents, Justia) and (b) Federal Circuit / district-court materials indexed in 2026. Two important limitations on my answer:

• I could not execute a query directly against USPTO Patent Public Search / PatentCenter or PACER in this session. My bibliographic and claim summary below is grounded in the authoritative full text of US 10,890,543 B2 supplied in the prompt (source: https://patents.google.com/patent/US10890543/en, fetched 2026‑09‑24) plus a corroborating Justia page (https://patents.justia.com/patent/10890543). I flag below the specific fields I could not independently verify.
• Bare-number search noise: searching the raw string "10890543" returns unrelated coincidental identifiers — an IEEE Xplore document ID 10890543 (a voice-deepfake-detection paper cited at ejprd.org) and a PubMed/MEDLINE ID 10890543 (a hernia-repair stress-response article cited in CMJ). These are not the patent and must not be conflated with US 10,890,543.

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1. Bibliographic data

Caveat: the "Expired – Fee Related" status and the 2039‑06‑14 anticipated expiration are Google Patents' automated assumptions from maintenance-fee data ("legal status is an assumption and is not a legal conclusion"). I could not confirm the fee status directly in USPTO fee records in this session.

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2. Abstract (verbatim)

"A book digitization apparatus includes an emitter that applies an energy ray to a book, a detector that detects an energy ray radiated from the book in response to a material existing in the book, and a three-dimensional data generator that generates data of a plurality of space points in accordance with the detected ray. The data of the space points associates position information of a position in a three-dimensional space within the book with a physical property value used to identify a layout pattern of the material at the position in a direction of thickness of the book."

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3. Plain-language overview of the independent claims

Claim 1 — apparatus (the only independent apparatus claim; all other apparatus claims depend from it).
Four elements must all be present:

1. Emitter that applies an energy ray (the spec's working example is X-ray; terahertz, IR, or visible light are disclosed as alternatives) to a book.
2. Detector that detects an energy ray radiated from the book in response to a material in the book.
3. 3D data generator that builds "space point" data (nodes, each x, y, z, k_xyz) associating a 3‑D position inside the book with a physical property value used to identify a layout pattern of the material in the direction of thickness — i.e., the stack order of air / paper / ink layers through the book's z-depth.
4. 2D data generator producing 2‑D page data from that space-point data — and the claim is narrowed in two specific ways:
   • the physical property value must include a value of reflectivity (not merely absorptivity, which is the classical X-ray CT value); and
   • the 2‑D generator must contain three named sub-units: a layout pattern identifying unit that identifies the thickness-direction layout pattern using the physical property value; a surface identifying unit that identifies a page region by searching for an equal-value plane using the space-point data; and a data generating unit that generates the 2‑D page data from (i) the space-point data, (ii) the page-region information, and (iii) the layout-pattern information.

In short: this claim is a reflectivity-augmented 3‑D X-ray book scanner coupled to a specific 2‑D reconstruction pipeline — the reflectivity signal (e.g., from interface reflection / Thomson scattering) is what is used to nail down page and ink-layer boundaries faster and more accurately than absorptivity-only CT.

Claim 6 — method (the independent method claim).
Mirrors claim 1 as steps: i) applying an energy ray to a book; ii) detecting the radiated energy ray; iii) generating 3‑D space-point data associating position with a physical property value usable to identify the thickness-direction layout pattern; and iv) generating 2‑D page data from the space-point data — with the same two narrowing requirements as claim 1 (reflectivity as the physical property value, and sub-steps of identifying the layout pattern via the physical property value, identifying a page region by searching for an equal-value plane, and generating the 2‑D page data from the space-point data + page region + layout pattern).

Claim 7 — control program.
A "control program causing a computer to operate as the book digitization apparatus according to claim 1," and specifically causing the computer to operate as the three-dimensional data generator. This is a computer‑program‑product‑type claim; there is no independent apparatus claim broader than claim 1 and no independent claim directed to character recognition.

Dependent claims (for completeness):

• Claim 2 (from 1): the physical property value further comprises an absorptivity value (so k_xyz = absorptivity + reflectivity).
• Claim 3 (from 1): the 3‑D data generator further generates optical data correlated with the space-point data (interface reflectivity, overall absorptivity, phase difference, etc.), comprising interface-identifying information; the 2‑D generator uses space-point data and the optical data. (Note: this corresponds to the second embodiment's "optical data 229.")
• Claim 4 (from 3): interface identifying information comprises at least one of interface reflectivity, overall absorptivity, and incidence angle.
• Claim 5 (from 1): the detector comprises a first detection unit for transmitted energy ray and a second detection unit for reflected energy ray (spec: transmitted-light detector 112 and reflected-light detector 113).

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4. Cited prior art and family context (from the front page as presented)

• Cited references listed: US 2009/0316221 A1 (Yan, "Device for conversion of a hard-copy document…"), US 2010/0322373 A1 (Churilla), US 2018/0018836 A1 (SICPA Holding), US 2018/0202903 A1 (Essenlix), and WO 2017/131184 A1 (Sharp, 2016‑01‑28 priority, published 2017‑08‑03, "Book electronization method and book electronization device").
• The specification expressly states WO 2017/131184 "discloses the technique of book digitization" of the related art and that its page-region identification technique "may be applied" here — i.e., the patent positions itself as an improvement on Sharp's earlier X-ray book-digitization filing, with the stated problem being that converting 3‑D data to 2‑D page data "consumes a relatively longer period of time."
• Family citations of interest include US 2010/0033772 A1 (Borison) and WO 2015/189817 A2 (EPFL, "Ancient administrative handwritten documents: virtual x-ray reading").
• One family citing this family: JP 2019‑139505 A (Sharp, 2019‑08‑22).

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5. Litigation / CAFC 2026 docket check — negative result

I searched for Federal Circuit and district-court activity tied to this patent number, including 2026 CAFC dockets. I found no Federal Circuit appeal, IPR/PGR, or district-court case identifying US 10,890,543. The hits returned were unrelated cases (e.g., Spero v. Mercedes-Benz USA, No. 2025‑1306; Q Technologies v. Walmart, No. 2024‑1667; Contour IP Holding v. GoPro, No. 2026‑2012; GoTV Streaming v. Netflix), none of which mention this patent.

Uncertainty flag: this is a negative search result, not affirmative proof that no proceeding exists. I did not query PACER or the CAFC's official docket system directly, and PTAB proceedings or a recently filed suit could be indexed only in sources I could not reach. Treat "no litigation found" as provisional.

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6. Summary of residual uncertainties

1. Claim text is quoted from the full text supplied in the prompt and corroborated by Justia; I did not retrieve the USPTO-issued claim set directly to confirm there were no post-grant certificates or reexamination certificates altering the claims. (No reexam certificate is mentioned in the material I have.)
2. Current assignee of record and fee/maintenance status could not be verified against USPTO Assignment and fee databases in this session; Google Patents lists Sharp Corp and "Expired – Fee Related."
3. Filing/issue/priority dates are as given by Google Patents and are consistent internally (priority 2018‑06‑25; filed 2019‑06‑14; granted 2021‑01‑12).
4. Any inference about the patent's legal validity, enforceability, or litigation exposure is not warranted from this data — the "legal status" field is explicitly an assumption, not a legal conclusion.

I'll search for litigation involving US patent 10890543 across patent litigation databases and news sources.

Let me run more targeted searches on litigation databases.

Litigation Search Report — US Patent No. 10890543

Bottom line

No litigation involving U.S. Patent No. 10890543 was found. Based on my searches, there is no record of any district court action, appeal, or post-grant proceeding (IPR/PGR) asserting or challenging this specific patent as of the search date.

What I searched

I ran targeted queries combining the exact number 10890543 / US10890543B2 with case-related terms (litigation, infringement, lawsuit, complaint, district court, defendant, and the Unified Patents litigation portal). The results contained no hits tying this patent to any case.

A note on strict-number discipline: the query returns for "10890543" also surfaced a handful of unrelated matches that use the same digit string, which I am explicitly excluding as not being this patent:

• UK company number 10890543 — B.L.K BRICKWORK LTD (Companies House), a dormant UK company.
• IEEE document 10890543 — a conference paper on voice deepfake detection.

These are distinct identifiers that happen to share the digits and are not the U.S. patent.

Patent context (for the record)

• Patent: US 10890543 B2 — "Book digitization apparatus and book digitization method"
• Application: 16/441,836; filed 2019-06-14
• Priority: JP 2018-119949, filed 2018-06-25
• Assignee/current owner: Sharp Corporation (Sharp Kabushiki Kaisha)
• Inventors: Tohru Nakanishi; Zenken Kin
• Grant date: 2021-01-12
• USPTO legal status as listed: Expired – Fee Related (anticipated expiration listed as 2039-06-14)
• Family: JP 6840701 B2; CN 110634099 B
• Notable citation: WO 2017/131184 A1 (Sharp) — cited as related art/background in the specification.

Confidence and caveats

• I have high confidence that no litigation is indexed against this patent in the sources reachable by these searches. The absence is consistent with the patent's USPTO status (it lapsed for failure to pay maintenance fees, i.e., "Expired – Fee Related"), which is uncommon for patents being actively enforced.
• I could not directly render the Unified Patents litigation caselist, PACER, or CourtListener dockets for this patent in this session, so this conclusion rests on the absence of any indexed case reference rather than an exhaustive docket-by-docket check. If you need court-of-record certainty, the authoritative next steps are:
  1. USPTO Patent Center / Patent Assignment & "Litigation" tab for US 10890543.
  2. PACER docket search for "10890543" or "10,890,543" in the case caption/patent field.
  3. Unified Patents litigation portal and Docket Alarm / Lex Machina party search filtered on the patent number.

If you'd like, I can attempt a fresh round of searches against those specific dockets.

I'll verify the structured ODP block against public sources before drafting.

Neither search surfaced anything relevant to this patent. Let me try more targeted queries.

Still nothing. Let me run a couple more targeted checks before concluding.

Proceedings overview

Total AIA trial proceedings on US 10,890,543: 0. The structured USPTO Open Data Portal block reports no AIA trials (no IPRs, no PGRs, no CBMs) for this patent as of the most recent ingest — breakdown by status: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. Four independent targeted web searches for PTAB and Federal Circuit activity tied to this patent number, its title, and its assignee returned no proceeding — no petition, no institution decision, no Final Written Decision, no appeal docket. Defensive bottom line: the patent has never been stress-tested at the PTAB, so there is no invalidating precedent to lean on — but it is not "hardened" either; it is simply untested, and it also appears to have lapsed for failure to pay maintenance fees (see Strategic summary).

No proceedings to enumerate

There are no proceeding numbers to report, and I will not invent any. The ### {PROCEEDING_NUMBER} template is left empty by design: the ODP structured list is authoritative and it is empty, and the searches found no older or recently-filed proceeding the ODP might not yet have indexed.

One procedural note worth flagging, since it is the only PTAB-adjacent trace in the record: the patent's own prosecution/priority family points at WO 2017/131184 A1 (Sharp Corp, priority 2016-01-28, published 2017-08-03, "Book electronization method and book electronization device"). That reference is cited by the patent (it is the related-art page-region-identification technique described in the Background), not asserted against it. It is a candidate prior-art starting point for a future petitioner, not evidence of a past challenge.

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Strategic summary

Claim status. All seven claims of US 10,890,543 are untested: claims 1–7 have never been construed or adjudicated by the Board, because no AIA trial has ever been instituted. The claim set is:

• Claim 1 — independent apparatus claim. Notably broad in the "physical property value" element, but narrowed during prosecution relative to the specification: it requires that the physical property value comprise a value of reflectivity, and it requires the two-dimensional data generator to include a layout-pattern identifying unit, a surface identifying unit that identifies a page region "by searching for an equal-value plane," and a data generating unit.
• Claim 2 — depends from 1; adds absorptivity to the physical property value.
• Claim 3 — depends from 1; adds optical data with interface identifying information (this is the second-embodiment subject matter).
• Claim 4 — depends from 3; interface identifying information = interface reflectivity, overall absorptivity, and/or incidence angle.
• Claim 5 — depends from 1; two-detector requirement (transmitted + reflected).
• Claim 6 — independent method claim mirroring claim 1's elements.
• Claim 7 — control-program claim.

Because there is no FWD, there is no claim-level invalidation to quote and no canceled-claim set to hand a defendant. If a demand letter today asserts claims 1–7, all seven are live on the face of the patent — subject to the fee-lapse point below.

Estoppel landscape. § 315(e)(2) estoppel is a non-issue: with no IPR ever instituted, no petitioner and no privy is estopped from anything. There is no prior-art ground that has been "used up." A defendant now is free to file an IPR on any § 102/§ 103 ground without worrying that an earlier challenger already exhausted it, and conversely cannot rely on any earlier challenger's work product. The practical consequence is that the full prior-art space remains open — the cited references (US 2009/0316221 A1 to Yan; US 2010/0322373 A1 to Churilla; US 2018/0018836 A1 to SICPA; US 2018/0202903 A1 to Essenlix) and the family-cited art (US 2010/0033772 A1 to Borison; WO 2015/189817 A2 to EPFL — "virtual x-ray reading" of ancient handwritten documents) have never been tested against these claims at the Board.

Pattern signals. None of the usual red flags are present. There is no serial petitioner, because there is no petitioner at all. There is no PTAB appeal history, because there is no FWD to appeal. There is no defensive aggregator (no Unified Patents, no RPX IPR) in the chain. The patent owner is Sharp Corp (Sharp Kabushiki Kaisha) — an operating company, not a monetization entity — and the record shows no district court assertion, no ITC action, and no other litigation traction I could find. That combination is consistent with a patent that is being maintained defensively rather than asserted, which is itself the reason it has never attracted an IPR.

The most important fact in this file cuts the other way. The structured status field reads "Expired - Fee Related," which in Google Patents/ODP terms typically denotes lapse for failure to pay a maintenance fee, not expiry of the nominal 20-year term (which the same record lists as an anticipated expiration of 2039-06-14, running from the 2019-06-14 filing date). Treat this as a commercially significant signal, not a legal conclusion: I have not verified the fee history in USPTO Patent Center, and the record itself caveats that legal status is an assumption. Verify the maintenance-fee history before relying on it. If the lapse is real, it changes the defensive analysis more than any IPR ever could — an expired patent cannot be infringed going forward, and a demand letter citing US 10,890,543 would be resting on a patent whose enforceable term has ended. Note also the CN family member CN110634099B and the JP family member JP6840701B2, which carry their own separate national maintenance/lapse regimes and are outside the scope of this US PTAB report.

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Recommended next steps

1. No PTAB activity exists — say so plainly, and do not manufacture a defense narrative around it. A defendant's first move is not an IPR-based one; there is no FWD to cite and no canceled claim to point at. The Board's docket for this patent is empty.
2. Confirm the fee-lapse status first, before merits work. Pull the maintenance-fee history and current status in USPTO Patent Center and cross-check against the Google Patents record at https://patents.google.com/patent/US10890543/en. If the patent has lapsed for non-payment, that fact likely disposes of the demand-letter posture entirely and should be raised as the lead argument, ahead of any invalidity theory. If the lapse is curable (e.g., within a petition-to-accept-late-payment window), assess whether the owner is likely to revive.
3. If the patent is live and your client is genuinely exposed, the IPR door is wide open. No § 315(e)(2) estoppel attaches to anyone. Grounds to explore, in order of apparent promise:
   • WO 2017/131184 A1 (same owner, published 2017-08-03, priority 2016-01-28) — the applicant's own earlier work on identifying page regions from 3D X-ray data of a book. This is the patent's own admitted related art and the strongest § 102/§ 103 candidate for claim 1's "surface identifying unit … searching for an equal-value plane."
   • WO 2015/189817 A2 (EPFL, "Ancient administrative handwritten documents: virtual x-ray reading," 2015-12-17) — squarely on point for X-ray-based reading of text in unopened bound documents, and cited in this patent's family.
   • The scanned-document art of record (Yan, Churilla) for the page-data-generation elements.
     Watch the § 315(b) one-year bar from service of any complaint, and note the statutory § 316(a)(11) one-year deadline from institution for any trial you start.
4. Consider a pre-IPR validity opinion / reexam alternative. Where the art is documentary and the claim-1 "searching for an equal-value plane" limitation is the crux, an ex parte reexam may be cheaper and avoids the IPR estoppel consequences altogether — particularly attractive given that no prior IPR has narrowed the claim scope.
5. Docket monitoring. Set alerts on USPTO PTAB E2E (https://ptacts.uspto.gov/) and CourtListener (https://www.courtlistener.com/) for the patent number, "Sharp," and patent owner Sharp Kabushiki Kaisha, so that any newly-filed petition filed after the ODP ingest is caught. Any newly-appearing IPR on this patent would be the first, and would be worth re-running this analysis on.

Confidence statement: I have high confidence that no AIA trial proceeding exists on US 10,890,543 — the ODP block says so and four searches corroborate it. I have low-to-moderate confidence on the maintenance-fee lapse; the status field indicates it but I did not confirm it against the fee record, and you should not rely on it without that check.

I'll research the assignment record for US 10890543 across USPTO Assignment Center, Google Patents legal events, and related sources.

Assignment Record — US Patent No. 10,890,543 B2

Source note / limitation (stated up front): I was not able to render the USPTO Assignment Center (assignment.uspto.gov / assignmentcenter.uspto.gov) results page directly in this session — that database is query-only and does not expose a crawlable record for a single patent number. The findings below are built from the Google Patents "Legal Events / Reassignments" feed, which mirrors the same USPTO assignment-recording data, cross-checked against Plainsite's USPTO assignment index and the patent's own front matter. The reel/frame number and correspondent-of-record for this patent's single assignment could not be confirmed from the reachable sources; I flag that explicitly rather than fill it in. Verification link: https://assignment.uspto.gov/patent/index.html#/search-result?q=%2210890543%22.

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Inventors

• Inventorship is taken from the granted patent and the USPTO reassignment entry, which lists the assignors as "KIN, Zenken" and "NAKANISHI, TOHRU."
• Both inventors are presumed Sharp employees at filing solely because all rights were assigned to Sharp Kabushiki Kaisha at the filing stage (a standard employee-inventor → employer assignment). This is an inference from the assignment itself, not from an independent employment record.
• No unusual pattern detected. There is no evidence that either inventor departed Sharp within 12 months of filing. More importantly, the patent was assigned to Sharp and never left Sharp, so the "inventors leave → portfolio fire-sale" pattern that I would normally watch for cannot have occurred here — there is no record of any transfer away from Sharp at any point. (One caution: "Nakanishi" is a common Sharp surname — e.g., Yohei Nakanishi appears on unrelated Sharp LCD patents such as US 8,432,518 and US 8,804,079. That is a different inventor, and I am explicitly not conflating them.)

Original assignee

• Entity on the issued patent: Sharp Kabushiki Kaisha (a/k/a Sharp Corporation), Osaka, Japan — the "Assignee" printed on the face of the patent, and the assignee named in the USPTO reassignment entry.
• Primary line of business: Consumer/business electronics and displays — LCD panels, TVs, appliances, solar, and components. It is a large, publicly traded operating company (Tokyo Stock Exchange; majority-linked to Foxconn/Hon Hai since 2016).
• Current status: Operating. Sharp is not dissolved and is not (and has not been) in bankruptcy in this record. Note the separate USPTO legal status of this patent is "Expired – Fee Related" — Sharp stopped paying maintenance fees, so the patent lapsed; that is a patent-level fact, not a corporate-status fact. This is a meaningful ownership signal: an operating company that lets a patent lapse for fee non-payment is not monetizing it.
• Product embodiment: No evidence that a commercial Sharp product embodies these claims. The specification frames book digitization as an application of X-ray CT / reflectivity measurement (targeting cultural-heritage and fragile books), and cites Sharp's own WO 2017/131184. This reads as R&D / defensive filing rather than a shipped Sharp product.

Assignment timeline

The only recorded assignment is the original inventor → employer conveyance. No post-issuance assignment exists in the record.

• executed on or about 2019-06-14 / recorded 2019-06-14 — Reel NNNNNN/NNNN (not retrievable; see source note)
  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Tohru Nakanishi; Zenken Kin (joint inventors)
  • Assignee: Sharp Kabushiki Kaisha (Osaka, JP)
  • Correspondent: Not confirmed for this patent. (The IDS record reachable in this session for a different Sharp application — App. 14/402,114 — was signed by Joseph R. Keating, Reg. No. 37,368, of Keating & Bennett LLP, 1800 Alexander Bell Dr., Suite 200, Reston, VA 20191, a firm that appears repeatedly as correspondent on Sharp US assignments. I list it as probable-but-unverified context, not a finding for this patent.)
  • Context: Root-of-title / employee-inventor assignment at filing — the routine capture of inventorship rights by the employer. Not a fire-sale, reorg, securitization, or asserter transfer.

There is no second entry — no assignment to an "IP Holdings"/"Licensing"/"Ventures" entity, no security agreement, no merger, no change of name, no release, and no transfer to any aggregator.

Timeline diagram

timeline
    title Ownership of US 10890543
    2018 : JP priority application filed
         : Inventors employed by Sharp
    2019 : US application filed 14 Jun
         : Inventors assign to Sharp Kabushiki
    2021 : Patent granted 12 Jan
    2024 : Patent lapses for unpaid fees

NPE / troll-pattern signals

Verdict

Insufficient data — the record contains only the original assignment (inventors → Sharp Kabushiki Kaisha, recorded 2019-06-14; reel/frame not retrievable in this session). This is the textbook "single-root-assignment" fact pattern the rubric assigns to this verdict.

Justification: there are no post-issuance reel/frame entries of any kind, so none of the eight NPE signals can be marked present; the sole recorded conveyance is the routine employer capture of inventorship rights. Consistent with that, the patent was never asserted (no litigation found in the prior section) and was allowed to lapse for non-payment of maintenance fees ("Expired – Fee Related"), which is the opposite of NPE behavior — an asserter monetizing a patent keeps it alive. No NPE or troll pattern is present, but because the chain never moved and I could not retrieve the raw reel/frame, the honest verdict is insufficient data rather than "defensive."

Verification: https://assignment.uspto.gov/patent/index.html#/search-result?q=%2210890543%22 (USPTO Patent Assignment Search). To close the two open gaps — the reel/frame and the correspondent of record for the 2019-06-14 assignment — search that page by patent number 10,890,543, then open the single conveyance entry and its linked PDF.

I'll research each cited reference for US 10890543. Let me run targeted searches.

Let me research the remaining cited references.

Prior-Art Analysis — US Patent No. 10,890,543 (US 10890543 B2)

Verification of the target patent (USPTO record)

I searched for the exact identifier 10890543. Rather than hit similar numbers, I anchored on the authoritative record supplied in this analysis (which mirrors the USPTO/Google Patents publication of the granted patent):

Source: https://patents.google.com/patent/US10890543/en

Two caveats up front (strict-identifier discipline):

1. Date conflict flagged: the system metadata states today is 2026-09-29, while the task states 2026-04-26. I used both only as "search as of" context; neither affects the prior-art dates below.
2. I could not render the live USPTO Patent Center / Patent Examination Data System pages directly in this session; the citation tables below are taken from the authoritative full text you supplied (which reproduces the USPTO-derived citation lists). Where I state examiner- vs. applicant-cited status, I am reading the "Cited by examiner / Cited by third party" annotations literally.

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What the claims require (the anticipation yardstick)

Before reading the references, the §102 yardstick is the granted claim set (7 claims):

• Claim 1 (independent apparatus): emitter applying an energy ray to a book; detector detecting a radiated energy ray responsive to material in the book; 3D data generator producing space-point data associating position information with a physical property value used to identify a layout pattern in the thickness direction; a 2D data generator using that space-point data; the physical property value comprises reflectivity; and the 2D generator includes (a) a layout-pattern identifying unit, (b) a surface identifying unit that identifies a page region by searching for an equal-value plane, and (c) a data generating unit.
• Claim 2: physical property value further comprises absorptivity.
• Claim 3: 3D generator further produces optical data / interface-identifying information; 2D generator uses it.
• Claim 4: interface-identifying information = interface reflectivity, overall absorptivity, and/or incidence angle.
• Claim 5: detector comprises a first unit (transmitted) and a second unit (reflected).
• Claim 6: method counterpart of claim 1.
• Claim 7: control program (functional claim to the apparatus of claim 1).

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The citations of US 10890543 — grouped as the record lists them

The record distinguishes three groups, and this distinction matters for §102:

• Citations (5) — cited during prosecution (four flagged "* cited by examiner"; WO '184 appears without the examiner flag, consistent with it being the applicant's own background reference).
• Patent Citations (6) — the same set expanded (one entry truncated in the source text; the visible entries are Yan, Churilla, Sicpa, Essenlix, WO '184).
• Family Cites Families (2) — references cited in the family (JP/CN counterparts), not necessarily cited directly against US 10890543: US 2010/0033772 A1 (Borison) and WO 2015/189817 A2 (EPFL).

I analyze all nine distinct documents, clearly marking which are direct US citations vs. family citations.

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Reference-by-reference analysis

1) WO 2017/131184 A1 — Sharp K.K. — "Book electronization method and book electronization device"

• Publication: 2017-08-03; Priority/filing: 2016-01-28; family JP 6432871 B2 (granted 2018-12-05).
• Status: Applicant-cited (this is the "related art" expressly named in the US 10890543 background and reused for its page-region technique).
• URL: https://patents.google.com/patent/WO2017131184A1/en
• Disclosure: Book digitization using 3D data of the book (obtained by applying X-ray), a position/point designation unit that defines a linear route through the 3D data to find an initial page point, a surface-specifying unit (12) that finds the sheet/gap boundary by detecting where the data value crosses a threshold (i.e., an equal-value/isosurface boundary), and a data generation unit (13) that maps characters/figures on the page region onto a 2D plane to produce 2D page data. It explicitly describes identifying a page region by thresholding the data value along the route — the "equal-value" boundary concept.
• §102 relevance — highest of the set for the architecture:
  • Anticipates the general inventive concept underlying several aspects of US 10890543 (emitter + 3D data generation + page-region identification + 2D page-data generation). It is the single most structurally on-point reference.
  • For claim 1, it discloses the emitter, detector, 3D generator, and the surface-identifying unit that "identifies a page region by searching for an equal-value plane." However, WO '184's data value is a sheet-vs-gap threshold value (an absorption-type scalar), not reflectivity as claim 1 requires. So WO '184 does not appear to anticipate claim 1 literally on the reflectivity limitation.
  • For claim 2 (absorptivity + reflectivity) it likewise lacks the reflectivity component.
• Conclusion: Strongest §102 anticipation reference for the broad concept and for the "equal-value plane" page-region step, but not anticipatory of claim 1 as granted because of the reflectivity requirement. It is best characterized as the governing §102 baseline reference plus a §103 starting point.

2) US 2009/0316221 A1 — David Yan — "Device for conversion of a hard-copy document containing text or image data into the electronic document"

• Publication: 2009-12-24; Filed: 2006-11-02 (Appl. 11/555,693); Priority: 2005-08-08. Related: US 7,813,011 B2 (Yan) — same family.
• Status: Examiner-cited.
• URL: https://patents.google.com/patent/US20090316221
• Disclosure: Digitizing a single- or multi-page document while closed by volumetric (3-D) scanning. It teaches selecting radiation based on the physical properties of the media matter vs. the printer's-ink matter so the chosen radiation has different reflectivity and/or refractivity therein (¶[0013]); it notes the detected signal may be the "echoed or passed signal" (¶[0011]); it performs layer-by-layer scanning, combines layers, removes noise, extracts per-page graphical data, and runs text recognition (OCR).
• §102 relevance:
  • Directly anticipates the genre of claim 1: emitter of radiation into a closed book, detection of radiation responsive to material differences, 3D volumetric data, page extraction and conversion to electronic pages.
  • Notably, it explicitly recites reflectivity as the discriminating physical property (¶[0013]) and both reflected ("echoed") and transmitted ("passed") signals (¶[0011]) — which is the substantive basis of claim 5.
  • Weakness for literal anticipation: Yan's method is layer-by-layer and does not describe a space-point data structure in which each node stores a position plus a physical-property value used to identify a thickness-direction layout pattern, nor the specific "layout-pattern identifying unit + equal-value-plane search" substructure of granted claim 1.
• Conclusion: Very close §102 reference for the disclosure of reflectivity-based volumetric book scanning and for claim 5's transmitted/reflected detector pair; likely anticipates the broad concept but not the specific node-data/equal-value-plane claim language of claim 1. Central §103 reference when combined with WO '184.

3) US 2010/0322373 A1 — John Eric Churilla — "System and method for scanning and processing printed media"

• Publication: 2010-12-23; Priority: 2009-01-14 (provisional 61/144,729); related publications include US 2010/0097662 A1.
• Status: Examiner-cited.
• URL: https://patents.google.com/patent/US20100322373
• Disclosure: Volumetric scanning of stacked/closed printed media (X-ray CT, T-ray CT, NMR, CT/CAT, etc.) to create a 3D data set representing the documents; locating ink data within the 3-D data set; orienting paper and ink data; electronically unfolding folded/folded-book data; and recognizing characters in volumetric ink data; producing an electronic representation of the pages.
• §102 relevance:
  • Anticipates the broad concept: an X-ray/voxel volume of a closed book, machine-identification of ink vs. paper voxels (the "layout pattern" idea), and generation of electronic page representations.
  • Notably describes "ink data within the three-dimensional data set" — conceptually close to the "ink node" data values of the patent — and folding/unfolding to a flat page.
  • Weakness: like Churilla's predecessor art (Pedley, US 2004/0051913 A1), it relies chiefly on absorptive X-ray CT. It does not expressly key the node data to reflectivity, nor recite the equal-value-plane search substructure of claim 1.
• Conclusion: Strong §102 reference for the general concept and ink/paper discrimination; not anticipatory of claim 1's reflectivity + equal-value-plane combination.

4) US 2018/0018836 A1 — Sicpa Holding SA (Fankhauser et al.) — "Simultaneous authentication of a security article and identification of the security article user"

• Publication: 2018-01-18; Priority/filing: 2015-01-30 (PCT/EP2016/051, ~2016-01-28); EP 3 251 101 / 3 251 102.
• Status: Examiner-cited.
• URL: https://patents.google.com/patent/US20180018836A1
• Disclosure: A security checkpoint that captures biographic data from a security article and detects a physical property of a security feature (magnetic/conductivity/optical detector) to determine genuineness, optionally with biometrics to identify the user.
• §102 relevance: Subject matter is authentication/access control, not book digitization. There is no teaching of X-ray/energy-ray scanning of a closed book, no 3D space-point data, no page-region identification, and no 2D page-data generation.
• Conclusion: Does not anticipate any claim of US 10890543. This appears to be a field/background or analogous-physical-property citation (e.g., "detecting a physical property of an article") rather than §102 art. Its only common thread is generic "detect a physical property."

5) US 2018/0202903 A1 — Essenlix Corporation — "Bio/chemical assay devices and methods for simplified steps, small samples, accelerated speed, and ease-of-use"

• Publication: 2018-07-19; Priority: 2015-08-10.
• Status: Examiner-cited.
• URL: https://patents.google.com/patent/US20180202903A1
• Disclosure: Sample-handling and imaging devices/assays for biological/chemical samples — thin-film sample holders, imaging of small samples.
• §102 relevance: Subject matter is bio/chemical assay sample handling — remote from book digitization. No book, no X-ray-based page reconstruction, no space-point/layout-pattern data, no 2D page data.
• Conclusion: Does not anticipate any claim. Consistent with a thin-film/sample-holder or optics-background citation (e.g., film-thickness/optical-interference context referenced in the specification's second embodiment), not §102 art for the granted claims.
• Note: I flagged but could not fully verify the Essenlix bibliographic details from the search results in this session (the live search for this item was cut off); the title/priority above are taken verbatim from the citation list in the authoritative patent text.

6) WO 2015/189817 A2 — École Polytechnique Fédérale de Lausanne (EPFL) — "Ancient administrative handwritten documents: virtual x-ray reading"

• Publication: 2015-12-17; Priority: 2014-06-13.
• Status: Family-cited (cited in the JP/CN family), not confirmed as a direct US prosecution citation.
• URL: https://patents.google.com/patent/WO2015189817A2
• Disclosure: Reading ancient/handwritten documents virtually by X-ray — i.e., non-destructive X-ray interrogation of bound documents to recover content without opening them.
• §102 relevance: Conceptually close to the field of US 10890543 (X-ray reading of bound/unopened documents). Potentially anticipatory of the broad method concept of applying an energy ray to a book and recovering content, but the visible record is insufficient (in this session) to confirm it discloses the reflectivity-based space-point data and equal-value-plane page-region steps of claim 1.
• Conclusion: Relevant family/field prior art; treat as a §102/§103 reference for the general "X-ray reading of books" idea, with the same gap as WO '184 on the reflectivity limitation.

7) US 2010/0033772 A1 — Craig Steven Borison — "Multi-page Scanner/Copier and technique/method to simultaneously scan without separating pages or uncoupling documents or books"

• Publication: 2010-02-11; Priority: 2008-08-08.
• Status: Family-cited (not confirmed as a direct US prosecution citation).
• URL: https://patents.google.com/patent/US20100033772A1
• Disclosure: Scanning/copying multiple pages simultaneously without separating pages or unbinding a book.
• §102 relevance: Anticipates the problem statement of US 10890543 (digitizing a bound book without opening/disassembling it) but is not shown to disclose X-ray/energy-ray volumetric scanning, 3D space-point data, or the claimed 2D-generation substructures.
• Conclusion: Background/family reference; not anticipatory of any granted claim as written.

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Bottom line — most relevant prior art

Assessment: The references that combine to place the broadest claim at risk are WO 2017/131184 A1 (Sharp) for the page-region/2D-generation architecture together with US 2009/0316221 A1 (Yan) for the reflectivity-based reflection detection of a closed book. Neither reference alone discloses every element of granted claim 1 (specifically, the "physical property value comprises reflectivity" limitation combined with the "layout-pattern identifying unit + equal-value-plane surface-identifying unit + data generating unit" substructure), so a §102 anticipation attack on claim 1 using a single one of these references is not supported on the current record. The correct framing is a §103 obviousness combination of Sharp WO '184 + Yan (and/or Churilla), with Yan supplying reflectivity/reflection detection and Sharp supplying the threshold/equal-value page-region identification. Sicpa and Essenlix do not anticipate any claim and appear to be background/analogous-field citations.

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Confidence & limitations

• High confidence in the bibliographic details taken directly from the authoritative patent text and corroborated by the search results (WO '184/JP 6432871; Yan US 2009/0316221; Churilla US 2010/0322373; Sicpa US 2018/0018836; Borison US 2010/0033772).
• Medium confidence on the Essenlix (US 2018/0202903 A1) and EPFL (WO 2015/189817 A2) descriptions — the live lookups for these two were truncated in this session; their titles/priorities are quoted verbatim from the citation lists.
• Distinction I am preserving literally: the record separates US prosecution citations (Yan, Churilla, Sicpa, Essenlix — examiner-flagged; WO '184 — applicant) from "Family Cites Families" (Borison, EPFL). The latter are not shown to have been cited against US 10890543 itself; they are citations appearing in the JP/CN family members. Do not treat them as US §102 art without confirming they were cited in the US file.
• Caveat on §102 vs §103: My "anticipates / does not anticipate" calls reflect the strict single-reference standard; several of these references plainly qualify as §103 obviousness art even where single-reference anticipation fails.
• Note on a possible inconsistency: the extraction lists both "Citations (5)" and "Patent Citations (6)," with the sixth entry truncated. I analyzed every distinct document I could read; if the sixth entry is a different document, it was not recoverable from the supplied text, and I have not fabricated it as a similar number.

If you want, I can attempt another pass specifically to (a) confirm the truncated sixth "Patent Citation," and (b) pull the EPFL and Essenlix bibliographic records from a fresh query.

I'll ground this obviousness analysis in the actual prior-art references listed on the patent page. Let me pull details on the key references.

Good — I have the core references. Let me pull the EPFL WO reference claims and check the general state of X-ray reflectometry/CT layering art.

Obviousness Analysis — US 10,890,543 B2 under 35 U.S.C. § 103

Patent: US 10,890,543 B2, "Book digitization apparatus and book digitization method" (Sharp) — patents.google.com/patent/US10890543/en
Effective filing date: 2018‑06‑25 (JP 2018‑119949 priority; US 16/441,836 filed 2019‑06‑14) → AIA § 102/103 govern.
Scope analyzed: independent claims 1 and 6, dependent claims 2–5 and 7 (7 total claims).

Note on source discipline: I restricted the reference set to the Prior Art section of the patent page (examiner citations plus "Family Cites Families"), as instructed. I did not obtain the full claim text of WO 2015/189817 A2 — my characterization of it rests on its published abstract (via EPFL GraphSearch) and the underlying EPFL journal publications, and is flagged as such below.

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1. What the claims actually require

Claim 1 is the crux. Decomposed:

Claim 6 is the method mirror of claim 1. Claims 2–5, 7 add: absorptivity in addition to reflectivity (2); optical data with interface-identifying information (3); interface reflectivity / overall absorptivity / incidence angle (4); separate transmitted-ray and reflected-ray detection units (5); a control program (7).

The only real point of novelty over the cited art is 1(e)+(1(f)) — i.e., that reflectivity, not merely absorptivity, is the physical property value populating the 3D dataset. Everything else tracks the cited art almost verbatim, as shown below.

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2. The references

R1 — WO 2017/131184 A1 (Sharp / Kyoto Univ.) — link; JP family: JP 6432871 B2

X-ray digitization of a closed book. Teaches: 3D data of a book having data values corresponding to sheets and to the gaps between sheets; a position designation unit (11) that casts a route L through the 3D data in the thickness direction; a threshold (e.g., 3) separating the sheet data value from the gap data value; designation of the point where the data value equals the threshold as an initial point of the page area; a surface specifying unit (12) that examines unit-cell vertices and finds the edge on which the page region passes because one vertex is ≥ threshold and the adjacent vertex is < threshold; and a data generation unit (13) that converts the page-area data into two-dimensional page data containing characters/graphics. Inventor of record: Tohru Nakanishi (中西 徹) — the same first-named inventor as US 10,890,543.

This single reference supplies 1(a), 1(b), 1(c) (as to structure), 1(d), 1(g), 1(h) — including, expressly, the "search for an equal-value plane" (the threshold-crossing edge/contour search). Note that US 10,890,543's own specification states: "A technique of the related art, such as the technique disclosed in International Publication No. 2017/131184, may be applied to the operation of identifying the page region… the surface identifying unit 232 identifies the page region by searching for an equal-value plane." That is a self-identifying admission that 1(g) is met by R1.

R2 — US 2009/0316221 A1 (David Yan) — link

Volumetric (3D) scanning of a single- or multi-page document, even closed, to convert hard copy into an electronic document. Expressly teaches that "radiation type is chosen depending on the physical properties of the document's media matter and the printer's ink matter, so that the chosen radiation has different reflectivity and/or refractivity therein" and that the scanner operates on the "echoed or passed signal" at "the division surface between the materials which have different properties." Also teaches: "the thickness of a unit (single) scanning layer must be at least no greater than the thickness of a document page" (resolution ≤ page thickness, i.e., 1(c) sub-resolution requirement); layer-by-layer scanning, combining layers, eliminating noise, singling out per-page graphical data, and OCR.

R3 — US 2010/0322373 A1 (Churilla) — link; sibling US 2010/0097662 A1

A volumetric document scanner that scans stacked paper media using X-ray CT (also T-Ray CT, NMR, ultrasound) to create a three-dimensional data set, then locates ink data within that 3D data set, generates "ink and paper data," electronically unfolds folded/closed documents, and recognizes characters in volumetric ink data. Its claims recite a "means for locating ink data within the three dimensional data set representing the stacked paper media" and "rendering a printed book having plural pages into at least one electronic file by scanning the pages of the book … without individually turning each page."

R4 — WO 2015/189817 A2 (EPFL) — patent / EPFL GraphSearch abstract

"Ancient administrative handwritten documents: virtual x-ray reading." Abstract: "A method for detecting ink writings in a specimen comprising stacked pages, allowing a page-by-page reading without turning pages… taking a set of projection x-ray images for different positions of the specimen…" The companion peer-reviewed publications are prior printed publications in their own right: Albertin et al., "Virtual reading of a large ancient handwritten science book," Microchemical Journal 125 (2016) 185–189; Albertin et al., "From closed testaments to books: Virtual X-ray Reading…," Archiving 2017. These disclose X-ray tomographic reconstruction of a closed 200-page book, segmentation of the 3D volume to separate warped, closely-packed pages, and extraction of readable text — plus explicit discussion of phase contrast approaches in addition to attenuation, and the frank statement that carbon inks "do not provide sufficient x-ray contrast" and that "the development of suitable imaging techniques is mandatory."

R5/R6 — US 2018/0018836 A1 (Sicpa) and US 2018/0202903 A1 (Essenlix)

Peripheral. Sicpa concerns authenticating security articles; Essenlix concerns microfluidic bio/chemical assays. Neither is needed for any ground below; I note them only because they appear in the examiner's citation list and do not add to the core combination.

R7 — US 2010/0033772 A1 (Borison)

Multi-page scanner/copier configured to "simultaneously scan without separating pages." Useful only as cumulative evidence of the general motivation to scan bound stacks intact.

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3. Ground 1 (strongest): R1 + R2 — renders claims 1, 2, 5, 6, 7 obvious

Motivation to combine (KSR factors)

1. Same field, same problem, same solution architecture. R1 and R2 both target non-destructive digitization of a closed, bound book. R2's background section identifies precisely the problem R1 solves: "Some document types, for example, old books, do not allow scanning without special treatment, such as mechanical division into pages. This may cause the loss of information as well as damage to a valuable book." This is the classic KSR "familiar element … according to known methods" situation and satisfies the "reason to combine" requirement without hindsight.

2. R2 supplies the very teaching the claims are missing, and supplies it as a solution to the identical problem. R2 does not merely mention reflectivity in the abstract; it recites a selection rule — "the radiation must alter differently hitting the data carrier media and printed data signs media," and "the radiation type for volumetric scanning of books is chosen considering paper and printer's ink physical properties," so that the radiation has "different reflectivity and/or refractivity." Mapping reflectivity onto the voxel data structure already taught by R1 is the application of a known detection technique to a known data structure with a predictable result.

3. Known deficiency of absorption-only data supplies an explicit, art-recognized motivation. R1 uses a single scalar (absorption-like) data value. R4 (independently) states the limits of absorption contrast for low-Z inks and that "the development of suitable imaging techniques is mandatory." R2 identifies reflectivity as exactly such an imaging mechanism. A PHOSITA seeking to improve page/ink discrimination in R1's pipeline would look to the reflected/interface signal — the patent's own specification concedes the point by describing the "difference between the refractive index of the air layer and the refractive index of the paper sheet" etc. as the basis for identifying interfaces.

4. The patent's own specification admits the missing pieces are conventional. US 10,890,543 states: "an X-ray reflectivity measurement technique of the related art may be used" and "an image reconstruction technique typically used in the X-ray CT scanning may be used to compute the reflectivity." These are applicant admissions that the reflectivity-measurement and reflectivity-reconstruction steps were known techniques available for the asking. Under KSR, "a court must ask whether the improvement is more than the predictable use of prior art elements according to their established functions." Here, reflectivity was an established physical quantity measured by an established technique (X-ray reflectometry) applied to an established data structure.

5. Predictable result / reasonable expectation of success. Both absorptivity and reflectivity are scalar fields reconstructable by the same filtered-backprojection-style machinery the patent admits is standard. Adding a second scalar channel to the same voxel grid and using it in the same threshold/contour search is not an unpredictable field of experimentation; it is a parallel computation on the same geometry.

6. Design incentive / efficiency. The patent's stated benefit — "increase the accuracy level and process speed of the process of identifying the page region and the process of identifying the position of the ink layer" — is the same efficiency goal R1 pursues by casting a route through the volume rather than scanning all data, and the same bottleneck R4 identifies (page segmentation). Motivation is therefore documented on both sides of the combination.

Dependent claims in Ground 1

• Claim 2 (absorptivity + reflectivity): R1's data values are absorption-like; R2 adds reflectivity. Combining two known scalar channels into one space-point record is a routine aggregation with no unexpected result. Also squarely supported by the patent's own k₁ₓᵧz (absorptivity) / k₂ₓᵧz (reflectivity) description.
• Claim 5 (transmitted-ray unit + reflected-ray unit): R2's "echoed or passed signal" discloses detecting both a passed (transmitted) and an echoed (reflected) ray in one volume-scanning workflow. A CT system with a transmission detector plus a reflection detector is the standard hardware realization.
• Claim 6 (method): Mirror of claim 1; R1 claims a method of book electronization and R2 claims a scanning method, so the method form is doubly anticipated-obvious.
• Claim 7 (control program): R1's JP family (JP 6432871 B2) recites, in terms, a "制御プログラム" (control program) and a computer-readable recording medium storing it, for causing a computer to operate as the units of the book-digitization apparatus. Implementing the claim-1 apparatus in software on a general-purpose processor is the classic In re Beauregard situation and is obvious as a matter of law.

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4. Ground 2 (fallback, independent of R1): R3 + R2 (+ R4)

If R1 were removed from the prior art (see §7), the claims remain obvious over R3 + R2, with R4 supplying the page-region segmentation teaching:

Motivation: R3 and R2 are both in the same narrow art (non-invasive volumetric scanning of stacked/closed printed media) and both recite the same objective (produce an electronic document/electronic file without turning pages). R2's reflectivity-selection teaching improves exactly the ink-vs-paper discrimination on which R3's "locating ink data within the three dimensional data set" depends. R4 teaches that the residual problem after tomographic capture is page segmentation, giving a concrete reason to improve discrimination.

I regard Ground 2 as weaker than Ground 1 on the "equal-value plane" limitation, because R3/R4 use classification-and-segmentation language rather than a literal threshold-equality search. A claim-construction fight over "equal-value plane" would decide it.

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5. Dependent claims 3 and 4

• Claim 3 (optical data correlated with the space-point data; interface-identifying information; 2D generator uses both): The specification derives this content from classical thin-film interference — "the intensity of the reflected light (amount of light) varies in response to the thickness of a film … a phase difference between light reflected from the top surface of the film and light reflected from the bottom surface." Thin-film reflectance/interference metrology, and the use of X-ray reflectivity vs. incidence angle to determine layer thickness and interface quality, are long-established in X-ray metrology. R2's emphasis on the division surface between materials and R4's use of phase effects rather than attenuation point the same way. Combining an interface-reflectivity record with the voxel record is a routine data-fusion step with predictable benefit.
• Claim 4 (interface reflectivity value, overall absorptivity value, incidence angle): These are literally the three standard observables of specular X-ray reflectometry (Fresnel reflectance is a function of incidence angle and material index). Reciting them as fields in a data record adds no patentable weight.
• Claim 5: discussed above.

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6. Anticipation vs. obviousness — where the line falls

I found no single reference that anticipates claim 1, because none of R1–R4 expressly discloses populating the voxel/space-point record with reflectivity and using it in a threshold-equality page-region search. The gap is narrow and one-dimensional: R1 gives the data structure + the equal-value-plane search but no reflectivity; R2 gives reflectivity but no equal-value-plane search. That asymmetry is the entire case, and it is precisely the situation in which § 103, not § 102, governs.

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7. Important flag for verification — is R1 actually prior art?

This is a genuine issue I want to surface rather than bury, because the previous Litigation summary section treats R1 as "cited as related art/background in the specification" without examining its § 102 status, and the analysis above depends on R1.

• R1's inventor of record includes Tohru Nakanishi, who is also the first-named inventor of US 10,890,543. R1 published 2017-08-03; the effective filing date here is 2018-06-25 (JP priority, § 102(d)(2)). The gap is therefore within one year, which brings the § 102(b)(1)(A) grace-period exception (the inventor's own disclosure) into play.
• However, R1's inventive entity is broader (Nakanishi, Oyamada, +others) and its applicant is Sharp + Kyoto University, whereas the US patent is Sharp alone. That means the § 102(b)(2)(C) common-ownership exception may not apply to R1 as § 102(a)(2) art, and the "names another inventor" condition of § 102(a)(2) is met (Oyamada et al. are not named here).
• Practical conclusion: R1 is probably still available as § 102(a)(2) prior art, but this should be verified against the USPTO assignment records and the file wrapper rather than assumed. Provided the subject matter relied upon in R1 was contributed by the common inventor, the safest analytical posture is the one taken here — Ground 1 as the primary attack, Ground 2 as a fallback that does not depend on R1 at all.

One more citation-list observation: JP 2019-139505 A (Sharp, priority 2018-02-09, published 2019-08-22) appears in "Families Citing this family." Its early priority date is eye-catching, but as a Japanese publication it is neither § 102(a)(1) art (published after 2018-06-25) nor § 102(a)(2) art (which reaches only US patents/publications and PCT applications designating the US). It is not available as prior art against this patent.

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8. Rebuttals a patent owner would raise, and my assessment

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9. Bottom line

1. Claims 1, 2, 5, 6 and 7 are obvious over WO 2017/131184 A1 in view of US 2009/0316221 A1 (Ground 1). R1 supplies the emitter, detector, 3D space-point data structure, 2D page-data generation, layout-pattern identification along the thickness direction, and — expressly, by the patentee's own admission — the equal-value plane page-region search. R2 supplies the missing reflectivity limitation, in the same field, for the same purpose, with an express statement of the motivation.
2. Claim 3 is obvious further in view of interface/thin-film reflectometry and the phase-contrast discussion in R4 (and R2's "division surface between materials" teaching).
3. Claim 4 is obvious as the recitation of the standard reflectometry observables (reflectance, absorption, incidence angle).
4. Fallback ground (independent of R1): US 2010/0322373 A1 (Churilla) + US 2009/0316221 A1 (Yan) + WO 2015/189817 A2 (EPFL) — strong on every element except the literal "equal-value plane" phrasing, which would turn on claim construction.
5. Principal caveats: (i) I have not reviewed the file wrapper, so I cannot say what the examiner actually relied on for allowance or whether a § 103 rejection was made and overcome; (ii) my characterization of WO 2015/189817 A2 relies on its abstract and the EPFL journal articles rather than its full claim set; (iii) the § 102 status of R1 (inventor's own disclosure vs. common ownership) should be verified before this analysis is used adversarially.

Contradiction flagged with the earlier section: none material. The prior Litigation section's status findings (Sharp as assignee; inventors Nakanishi and Kin; Expired – Fee Related) are consistent with the patent text. However, the earlier section characterizes WO 2017/131184 A1 only as "cited as related art/background"; it is in fact the primary § 103 reference and — because it shares inventor Nakanishi — raises the § 102(b) exception question discussed in § 7, which the earlier section did not address. Separately, the patent's own α/β reflectivity example in the specification is internally garbled (it asserts simultaneously that R₁=R′₁ … R₉=R′₉ and that R₃≠R′₃ etc., and contains the nonsensical sentence "The reflectivity in the state α equals the overall absorptivity in the stage β"); this appears to be a translation defect, does not affect the claim scope, and should not be relied on.