US 6594213

I'll verify the patent details against live sources before summarizing.

US Patent 6,594,213 B1 — Verification Summary

Source check: I searched for the exact number 6594213 (and 6,594,213). Live results (FreePatentsOnline, Google Patents, Stanford NPE database, MediaTek financial reports) are consistent with the authoritative full text supplied. No search result produced a different patent under this number, so no search-vs-training conflict arose.

Bibliographic data

Notable provenance detail: the patent states it was preceded by a related Sanyo family (priority to JP 11-331417), and it is in the same family as US 7,106,675, US 7,167,427, and US 7,149,167 (all Sanyo, same 1999-11-22 priority).

Abstract (as issued)

A data recorder that prevents buffer underrun errors includes a buffer memory for temporarily storing data to be written to a recording medium and an address memory connected to a buffer memory. The address memory stores an address of the recording medium or an address of the buffer memory when data writing is interrupted. A synchronizing circuit sequentially reads data from the medium and data stored in the buffer memory prior to the interruption and synchronizes the read and stored data. A restart circuit restarts data writing when an address of data read from the medium or an address of data read from the buffer memory matches the address stored in the address memory.

Plain-language overview of the independent claims

• Claim 1 (data recorder apparatus): A recorder has (a) a buffer memory holding data before it is written to the medium, (b) an address memory that saves either the medium address or the buffer address at the moment writing is interrupted, (c) a synchronizing circuit that reads back the already-written data from the medium and the still-buffered data preceding the interruption and aligns (synchronizes) them, and (d) a restart circuit that resumes writing once the medium-side or buffer-side read address matches the saved address. The key wrinkle: if that match occurs before synchronization has finished, the restart is suspended and the read-and-synchronize cycle is repeated — i.e., a built-in retry loop that guards against a premature restart after a disturbance.

• Claim 4 (data recorder, retry-focused): Adds an interrupt circuit that stops recording upon detecting a "first state" where data continuity could be lost (e.g., buffer underrun risk). The address memory stores two addresses — the medium location and the buffer location at interruption. When a "second state" (continuity loss unlikely) is detected, the synchronizing circuit reads from positions preceding both addresses and synchronizes. A restart circuit restarts recording from one of the saved addresses once synchronization completes, and a retry determination circuit retries synchronization if it cannot be completed by the time the read address reaches the saved address.

• Claim 5 (data recorder, hardware-block claim): The most detailed independent claim. Recites an encoder (buffer memory → encoded recording data), a recording unit, a reproduction unit, an address generation circuit producing a "reproduction recording address," a recording address memory storing an "interruption recording address," a first location detection circuit comparing the two to emit a first match signal, a buffer address memory storing an "interruption buffer address," a second location detection circuit comparing the read buffer address to it to emit a second match signal, an interrupt circuit that halts the encoder on detection of the first state, a synchronizing circuit reading from addresses preceding both saved addresses, and a retry determination circuit that repeats synchronization until the first and second match signals are generated simultaneously, then authorizes restart.

• Claim 9 (method claim): A method comprising: encoding data to make first encoded data; recording it on the medium; when recording is interrupted, reproducing the recorded data to make reproduced data; separately encoding data corresponding to the recorded data to make second encoded data; synchronizing the reproduced data with the second encoded data; restarting recording if the two are synchronized before reproduction of the recorded data is complete; and otherwise repeating the reproduce → re-encode → synchronize cycle.

Claim-drafting note: Claim 5 recites "...a first location detection circuit connected to the address generation circuit memory and the recording address memory..." — the term "address generation circuit memory" has no clear antecedent basis earlier in the claim (the claim recites an "address generation circuit"). A reader should treat that as literal claim language, not a typo to be corrected.

Litigation / CAFC 2026 check (with explicit uncertainty)

• CAFC 2026 dockets: My searches returned no Federal Circuit docket, appeal, or PTAB proceeding in 2026 involving patent 6594213. The Federal Circuit filings surfaced by search (e.g., Greenthread, LLC v. Semiconductor Components Industries, LLC, No. 26-1646) involve different patents and are unrelated to 6594213. I could not confirm a negative, so I state it as: no evidence found of a 2026 CAFC matter for this patent; absence of a hit in my search is not proof of nonexistence.
• Known past litigation (confirmed by search):
  • Sanyo Electric Co. Ltd. v. MediaTek Inc., C.D. Cal. case 2:06-cv-01225 (the Stanford NPE database entry for patent 6594213 lists this case; MediaTek's 2006 financial reports confirm Sanyo asserted US 6594213 and US 6487616 counter-claims, later consolidated/withdrawn).
  • A Texas Eastern District Court case 6:05-cv-00323 is listed on the patent's litigation record (listed as "Critical").
• Because the patent is recorded as Expired – Lifetime with an adjusted expiration of 2021-09-02, a 2026 merits appeal would be unusual; any 2026 activity would most likely be a remnant of an earlier proceeding rather than new infringement litigation. I have no authoritative 2026 record either way.

If you want, I can drill into the specific EP/JP/KR/TW family members or the dependent claims 2, 3, 6, 7, 8 next.

I'll research litigation involving US patent 6594213. Let me search multiple sources.

Let me gather more details on the specific cases.

Let me dig deeper into the specific California case and its details.

Litigation Involving U.S. Patent No. 6,594,213

Bottom line: I found two U.S. district‑court proceedings tied to U.S. Patent No. 6,594,213 ("Data recorder," Sanyo Electric). Both are facets of the Sanyo–MediaTek dispute (2005–2008): the '213 patent was not asserted by Sanyo as a standalone complaint, but rather as a counterclaim that was severed from the Texas action and moved to California, where it was promptly dismissed. I found no CAFC appeal, no ITC action, and no later assertion of the '213 patent by any subsequent owner (the patent was reassigned to Semiconductor Components Industries, LLC in 2011 and expired in 2021).

Caveat: I was able to corroborate these from the Google Patents litigation listing, the Stanford NPE Litigation Database, Public Access to Court Electronic Records–derived docket summaries, contemporaneous MediaTek financial statements, and a settlement press release. I could not independently pull the PACER dockets in this session, so some procedural dates below rest on secondary sources and are flagged accordingly.

Case 1 — Sanyo's '213 assertion (California)

Sources: Google Patents litigation entry for 2:06-cv-01225 (https://patents.google.com/patent/[US6594213](/patent/US6594213)/en); Stanford NPE Litigation Database, patent 6594213 (https://npe.law.stanford.edu/patent/6594213); MediaTek Q3 2006 financial statements (https://www.mediatek.com/hubfs/MediaTek%20Assets/Pdfs/Financial%20Reports/2006/Q3-Report.pdf) and Q4 2006 consolidated results.

Case 2 — The Texas action in which '213 arose as a counterclaim

Sources: Google Patents litigation entry for 6:05-cv-00323; ExParte docket summary (https://ai-lab.exparte.com/case/dct/txed/6:05-cv-00323/mediatek-inc-v-sanyo-electric-co-ltd) (filed 8/31/05; status Closed; E.D. Tex.); Second Amended Complaint (https://insight.rpxcorp.com/litigation_documents/[2377627](/patent/2377627)); Markman orders (https://www.govinfo.gov/content/pkg/USCOURTS-txed-6_05-cv-00323/pdf/USCOURTS-txed-6_05-cv-00323-0.pdf).

Related resolution: Sanyo–MediaTek global settlement

The broader dispute was settled. According to a press release, Sanyo and MediaTek amicably resolved their U.S. patent disputes, covering:

• Sanyo's California claims against MediaTek and its customers ASUSTek Computer, Inc. and ASUS Computer International; and
• MediaTek's Texas claims against Sanyo and Sanyo North America Corporation.

Both matters were to be dismissed with prejudice, and the parties exchanged cross‑licenses under the asserted patents. (An attorney account of the Texas case confirms the parties settled the night before opening argument.) Note: this settlement post‑dates the April 28, 2006 dismissal of the '213-specific California case, so the '213 patent itself appears to have dropped out of the dispute in April 2006 rather than being resolved by the later settlement.

Sources: CDRInfo, "Sanyo and MediaTek Reach Settlement in Patent Infringement Litigation" (https://cdrinfo.com/d7/content/sanyo-and-mediatek-reach-settlement-patent-infringement-litigation); Sheppard Mullin attorney interview (https://www.sheppardmullin.com/assets/htmldocuments/1191.pdf).

What I did not find

• No Federal Circuit appeal specifically involving the '213 patent.
• No ITC (Section 337) investigation involving the '213 patent.
• No later NPE/assertion activity — despite the patent's 2011 assignment to Semiconductor Components Industries, LLC (ON Semiconductor), I found no litigation asserting '213 by that entity or any other party.
• No other litigants (e.g., other CD‑R/optical-drive makers) asserting or being sued on the '213 patent.

Caveat on completeness: My findings rely on publicly indexed litigation databases and secondary sources rather than a direct PACER pull. If you need certified docket confirmation, the two docket identifiers to retrieve are 6:05-cv-00323 (E.D. Tex.) and 2:06-cv-01225 (C.D. Cal.).

Note on identifiers: I have kept the case numbers exactly as reported (6:05-cv-00323 and 2:06-cv-01225) and the asserted patent numbers exactly as they appear in the sources (U.S. 6,594,213; U.S. 6,487,616; U.S. 5,867,819). No auto-correction has been applied.

I'll verify the structured "no proceedings" finding against live sources before writing anything up.

Let me run a few more targeted checks for any AIA proceeding, reexamination, or appeal tied to this patent.

PTAB / AIA Trial Proceedings — US 6,594,213 B1

Verification note before the analysis: The canonical structured block in this prompt ("PTAB proceedings on file") states: "The USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest." I treated that as controlling and ran independent web checks to see whether any proceeding existed that the ODP ingest had missed (searches for the patent number combined with IPR/PGR/CBM prefixes, "PTAB," "reexamination," and Federal Circuit terms, plus the Sanyo/MediaTek litigation trail). All searches came back empty of any AIA trial record for 6594213. No proceeding number was surfaced, so none is reported — I will not invent one.

Proceedings overview

Total AIA trial proceedings on file: 0 (0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials). This is a "no-PTAB-history" patent, and the defensive posture that gives a defendant is genuinely unusual — but not for the flattering reason the framing assumes. The patent was never put through an IPR because it was litigated in 2005–2006, years before the AIA created AIA trials (first IPR available 2012-09-16), and by the time AIA trials existed the disputes had already been dismissed and the patent later lapsed. So a defendant today inherits an un-hardened patent — no claim has ever been tested — but also an expired one (adjusted expiration 2021-09-02), which means the practical question is not "can I invalidate it" but "can the owner assert a live claim at all." No IPR estoppel, no FWD, no surviving-claim record exists to lean on.

Proceedings

(None. There is no proceeding to report for this patent. Rather than fabricate a section per the template, here is the affirmative evidence of absence and why.)

No AIA trial proceeding on file — US 6,594,213 B1

• Type: N/A — no Inter Partes Review, Post-Grant Review, or Covered Business Method review exists for this patent.
• Canonical source: USPTO Open Data Portal structured block for this patent returns no AIA trial proceedings (as of the most recent ingest).
• Corroborating checks (2026-09-28):
  • Web search for 6594213 combined with IPR2013 … IPR2020 identifiers returned no petition or trial for this patent.
  • Web search for Sanyo + 6,594,213 + reexamination terms returned no ex parte or inter partes reexamination certificate for this patent.
  • Web search for 6594213 + "Federal Circuit" returned only the Sanyo v. MediaTek district-court trail — no appellate docket, no PTAB appeal.
  • The Stanford NPE Litigation Database entry for patent 6594213 lists only district-court litigation (Sanyo Electric Co. Ltd v. MediaTek Inc., C.D. Cal. 2:06-cv-01225), with no PTAB entry.
• Why there is no PTAB history (chronology):

• Appeal: none found. No PTAB FWD exists to appeal, and no CAFC matter tied to 6594213 surfaced.
• Defensive value: There is no prior PTAB outcome to borrow. A defendant cannot point to a canceled claim or an instituted trial; the invalidity case must be built from scratch. However, the practical leverage is the expiration (2021-09-02) and the 2006 dismissal of the only asserted litigation — not a hardened patent.

Strategic summary

Claim status — CANCELED / SUSTAINED / UNTESTED. Every claim of 6594213 is UNTESTED. All nine claims (independent claims 1, 4, 5, and 9; dependent claims 2, 3, 6, 7, 8) issued as granted and no claim has ever been canceled, confirmed, or narrowed by the PTAB. Because none of the earlier Sanyo/MediaTek litigation produced a merits validity judgment (the C.D. Cal. case was dismissed in April 2006 before any AIA-era review existed), there is also no court-side claim-construction or invalidity record to import. Contrast this with the other side of the same family: 6594213 sits in the Sanyo 1999-11-22 priority family alongside US 7,106,675, US 7,167,427, and US 7,149,167 — so a litigant could mine those siblings' histories for claim-drafting and prior-art context, but none of that activity is a PTAB outcome on this patent.

Estoppel landscape. Because there is no IPR/PGR and thus no final written decision, 35 U.S.C. § 315(e)(2) estoppel never attached to anyone. There are no barred petitioners, no privies, and no "grounds raised or reasonably could have been raised" limitation. Practically, that means all prior-art grounds remain available to a current defendant — the full § 102/§ 103 space that a PTAB petitioner would have been limited to (patents and printed publications) is unencumbered. The only timing overlay is the § 315(b) one-year bar, which runs from service of a complaint alleging infringement and is irrelevant if no such complaint is on file.

Pattern signals. No defensive aggregator appears in the chain — Unified Patents is not in the 6594213 provenance (the Unified litigation links in the patent record are district-court case-links, not PTAB filings). There is no repeat-petitioner pattern because there are no petitioners at all. The patent owner (now Semiconductor Components Industries / ON Semiconductor) has not pursued any PTAB appeal on this patent, consistent with there being nothing to appeal. The one notable pattern is a product-company-vs-product-company dispute (Sanyo asserting against MediaTek over optical-storage ICs), not an NPE campaign — and it ended in 2006.

Recommended next steps

• If you are a defendant today: do not budget for an IPR-based defense premised on an existing PTAB record — there is none. Confirm the assertion posture first: read the patent's legal status (Expired – Lifetime; adjusted expiration 2021-09-02) on the Google Patents record and ask the asserting party to identify (a) the live claim being read on your product and (b) the damages period within the pre-expiration term. If the demand letter maps to claims 1–9 with no live term theory, the more efficient response is a damages/expiration challenge, not an invalidity trial.
• Validity work, if needed: because there is no PTAB FWD and no § 315(e)(2) estoppel, you are free to raise any patents/printed-publications combination in district court or in a fresh petition. Mine the sibling Sanyo family (US 7,106,675; 7,167,427; 7,149,167) and their prosecution histories for the closest art to the claim 5 "location detection circuit / retry determination circuit" architecture.
• Timing / IPR mechanics, if you nonetheless want a PTAB route: IPRs can be filed against expired patents (Phillips-style construction applies and no claim amendment is available), but note the § 315(b) one-year clock from any infringement complaint, and the Board's statutory 1-year trial deadline from institution (35 U.S.C. § 316(a)(11)). Under current Director practice, discretionary-denial gates apply at institution — see the Board's PTAB E2E / public-information portal for filing mechanics and the USPTO PTAB Decisions repository.
• Plainly stated: there is no PTAB activity on file for US 6,594,213 B1. The absence is itself informative — but here it reflects a patent that was asserted before AIA trials existed and that has since expired, not a patent that was challenged and survived.

Caveat on completeness: I could not prove a negative. My searches returned nothing, and the canonical ODP list is empty, but a very recent petition that has not yet been ingested, or an unindexed post-2012 filing, cannot be ruled out by search alone. If you have a litigation or assertion date, the fastest confirmation is a direct docket pull on PTAB E2E and CourtListener filtered to the patent number.

I'll verify the assignment record details against live sources before building the reconstructed chain.

Let me search for the specific reel/frame records and correspondent details.

Let me search for the specific recording details and correspondents.

Assignment Reconstruction — US 6,594,213 B1 ("Data recorder")

Verification note on source access: I could not open an authenticated session against assignmentcenter.uspto.gov or assignment.uspto.gov from this environment, and the live-search budget for this task was exhausted before I could pull the individual reel/frame member rows. What follows is reconstructed from (a) the authoritative Google Patents legal-events record supplied in the patent text, and (b) SEC/assignee corroboration retrieved by search. Where a reel/frame or correspondent value is not in hand, I say so explicitly rather than guess. Treat every reel/frame below as verified-only-where-cited; the rest are marked [not retrieved].

Inventors

Unusual-pattern check: No departure/fire-sale pattern is determinable from the record. The only signal worth noting is the opposite of a red flag: Hayashi is a repeat Sanyo inventor in this same family — he is the named inventor on the sibling applications surfaced in the "Cited By" list (US 2001/0006498, US 2001/0006495, US 2001/0006496, and US 2002/0101803, all "Data recorder" / "Controller of data recorder," priority 1999-12-27 and 2001-01-31). That is a career inventor at one operating company, not an inventor exiting ahead of a sale.

Original assignee

Sanyo Electric Co., Ltd. (Osaka, Japan) — a large, publicly traded consumer-electronics and components manufacturer (batteries, consumer AV, home appliances, and a substantial semiconductor division). It shipped product in the relevant field: the patent is directed to a CD-R optical-disc recorder, and Sanyo was an active optical-disc-drive and optical pickup/controller supplier. The claims recite a full drive control architecture (spindle servo, optical head, ATAPI/ATIP decode, encoder, buffer memory) — the sort of thing an operating drive maker actually builds.

Current status of the original assignee: Sanyo Electric was absorbed into Panasonic (Panasonic's stake-building began 2008; full subsidiary status 2011) and the Sanyo brand was progressively wound down. Sanyo's semiconductor business — SANYO Semiconductor Co., Ltd. — was divested to ON Semiconductor via its subsidiary Semiconductor Components Industries, LLC ("SCI LLC"), closing 2011-01-01. So the original assignee is best described as acquired/absorbed (not dissolved in bankruptcy), with the patent-bearing semiconductor unit carved out and sold to an operating acquirer.

Assignment timeline

1. 2000-11-21 (executed) / 2000-11-21 (recorded) — Reel [not retrieved]

   • Conveyance: Assignment
   • Assignor: Hayashi, Koji (inventor)
   • Assignee: Sanyo Electric Co., Ltd.
   • Correspondent: [not retrieved]
   • Context: Ordinary inventor-to-employer assignment executed on the filing date — initial ownership capture.

2. 2011-07-14 (recorded) — Reel [likely 026594 / ~0385 — see note]

   • Conveyance: Assignment (part of the SANYO Semiconductor acquisition)
   • Assignor: Sanyo Electric Co., Ltd.
   • Assignee: Semiconductor Components Industries, LLC
   • Correspondent: [not retrieved]
   • Context: Strategic acquisition — Sanyo's semiconductor/IP assets sold to ON Semiconductor (closing 2011-01-01; the assignment recorded 2011-07-14). ON Semiconductor's 2011 10-K confirms it obtained ~1,214 U.S. patents in the SANYO Semiconductor transaction. Not a fire-sale or bankruptcy.
   • Note on reel: Google Patents records a later corrective assignment (2014-05-06) stating it corrects "the incorrect #12/577882 previously recorded on reel 026594, frame 0385." That corrected record corresponds to the Sanyo→SCI LLC transfer, so the 2011 assignment is recorded at or near 026594/0385. I flag this as inferred from the corrective's own cross-reference, not from a direct member row.

3. 2014-05-06 (recorded) — Reel [not retrieved] (corrects 026594/0385)

   • Conveyance: Correction (Corrective Assignment)
   • Assignor: Sanyo Electric Co., Ltd.
   • Assignee: Semiconductor Components Industries, LLC
   • Correspondent: [not retrieved]
   • Context: Administrative clean-up of the 2011 record, which had mis-identified an unrelated application (No. 12/577,882). No change in beneficial ownership.

4. 2016-04-15 (recorded) — Reel 038620 / 0087 (the security-interest record expressly cited by the later corrective and release)

   • Conveyance: Security Interest (grant of security)
   • Assignor: Semiconductor Components Industries, LLC
   • Assignee: Deutsche Bank AG, New York Branch
   • Correspondent: [not retrieved]
   • Context: Securitization/financing — the patent pledged as collateral in a corporate credit facility. Not an ownership transfer.

5. 2016-08-25 (recorded) — Reel [not retrieved] (corrects 038620/0087)

   • Conveyance: Correction (Corrective Assignment — to fix an incorrect patent number, 5,859,768, and to recite the receiving party's collateral-agent role)
   • Assignor: Semiconductor Components Industries, LLC
   • Assignee: Deutsche Bank AG New York Branch, as Collateral Agent
   • Correspondent: [not retrieved]
   • Context: Administrative correction to the security-interest record; formalizes Deutsche Bank's role as collateral agent. No new ownership.

6. 2023-06-22 (recorded) — Reel [not retrieved] (releases 038620/0087)

   • Conveyance: Release (Release of Security Interest)
   • Assignor: Deutsche Bank AG New York Branch, as Collateral Agent
   • Assignee: Semiconductor Components Industries, LLC / Fairchild Semiconductor Corporation
   • Correspondent: [not retrieved]
   • Context: Lien discharge — collateral released as the credit facility wound down. Leaves SCI LLC as clean, unencumbered owner.

Correspondent finding (required call): I cannot make the repeat-correspondent call. The recording correspondents for links 1–6 were not retrievable in this session, so I will not assert a recurrence. The only attorney-of-record fact I can state from the authoritative text is the prosecution agent — Fish & Richardson P.C. (BO) — which is a large general-practice IP firm doing both operating-company and, historically, assertion-side work; a single appearance there would not be probative anyway. If you re-run this from Assignment Center and the same name/firm appears as correspondent on the 2011 and 2016 recordings, that would be a meaningful (but not by itself dispositive) tell.

Timeline diagram

timeline
    title Ownership of US 6594213
    2000 : Inventor Hayashi assigns to Sanyo
    2003 : Patent issued
    2005 : Sanyo sues MediaTek in EDTX
    2011 : Sanyo Semiconductor sold to SCI LLC
    2014 : Corrective assignment recorded
    2016 : SCI grants security interest to Deutsche Bank
    2023 : Deutsche Bank releases the security interest

NPE / troll-pattern signals

Aggregate read: Zero of the eight NPE signals are affirmatively present; one (repeat correspondent) is genuinely unclear only because reel-member data was not retrievable. The chain shows the classic life-cycle of an operating-company patent: inventor assignment → product-company owner → asserted by that owner against a direct competitor → owner's division sold to a larger operating company → patent pledged as loan collateral → lien released.

Verdict

Operating-company assertion.

The chain is Sanyo Electric (an operating optical-disc/product maker) asserting its own patent against MediaTek in E.D. Tex. 6:05-cv-00323 and C.D. Cal. 2:06-cv-01225, followed by a negotiated sale of Sanyo's semiconductor business to ON Semiconductor's operating subsidiary SCI LLC (recorded 2011-07-14, correcting record at reel 026594/0385), then a pledge to Deutsche Bank recorded at reel 038620/0087 (2016-04-15) and its release on 2023-06-22. Every owner in the chain sells products; no licensing-only shell, no known asserter, no cascading LLC transfers, and no pre-litigation transfer-on-the-eve-of-suit appears. The lone caveat is that the historic assertion (2005–2006) is by the then-owner Sanyo, not by today's owner SCI LLC, and no current litigation by SCI LLC was found — so this is "operating-company assertion" in the historic, fact-specific sense, not a live NPE situation.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 6594213) — and cross-check the same number in USPTO PatentCenter's "Assignment" tab. I recommend pulling the member rows for the 2011 and 2016 recordings specifically to fill the two [not retrieved] correspondent fields; that is the one open question that could, in principle, move signal #3.

Caveats on confidence: Reel/frame values for links 1, 2 (inferred), 3, 5, and 6 were not independently retrieved; only 026594/0385 and 038620/0087 are directly evidenced (via the corrective/release cross-references quoted on Google Patents). Correspondent names for all assignment links are unknown and are not asserted. No 2026 Federal Circuit or PTAB activity for this patent was found in the prior verification pass — absence of a hit is not proof of absence, and the patent's adjusted expiration (2021-09-02) makes new assertion litigation unlikely.

I'll verify the patent on live sources and pull its citation record before analyzing prior art.

Let me locate the citation record (references cited) for this patent.

I have the family-member citation list. Now let me pin down the exact "References Cited" on the US 6,594,213 front page.

Prior-Art Analysis — US 6,594,213 B1 ("Data recorder")

Scope note / method. The tool available to me is a web search, so I queried patent databases (Google Patents, FreePatentsOnline, Justia) rather than the USPTO PatentCenter/Patent Full-Text interface directly. I searched the literal string 6594213 and US 6,594,213 B1 only; no other patent number surfaced under those queries, so the number identifies the document summarized earlier (Sanyo, Koji Hayashi, filed 2000-11-21, priority JP 11-331417 of 1999-11-22, issued 2003-07-15).

1. Important discrepancy to flag up front

The authoritative full text you supplied contains a "Cited By (24)" list (22 publications that cite US 6,594,213 — i.e., forward citations) but it does not contain a "References Cited" / "Patent Citations" list (the backward citations, i.e., the prior art that was before the examiner). Since "prior art" and "§ 102 anticipation" only make sense for backward citations, I retrieved those separately. Two retrieval paths returned two partly different lists, and I could not fully reconcile them within the tool budget — I report both and mark them:

• List A — the search-report citations for the same invention, from the EP family member EP1102261A3 (Google Patents): https://patents.google.com/patent/EP1102261A3/en
• List B — foreign documents shown on the US record at FreePatentsOnline: https://www.freepatentsonline.com/[6594213](/patent/6594213).html

Treat List A as the best-grounded description of the art the family was examined against; treat List B as needing confirmation against the USPTO front-page image (I list it provisionally). I also could not retrieve the U.S. patent documents portion of the US front page, so any U.S. patent references cited on the face of US 6,594,213 are not identified here — that is a real gap, stated rather than filled.

2. Backward citations (List A — family search report, same invention)

A-1. EP 0 543 446 A1 — "Information recording device, record carrier and information reading device"

• Applicant: Koninklijke Philips Electronics N.V. (NL)
• Filing/priority: 1991-11-19 · Publication: 1993-05-26
• Description: A recording/reading device in which a buffer memory temporarily stores incoming data blocks and control means periodically interrupt read-out, return the scanning spot to a previous track location, and resume read-out when the spot again reaches the location where read-out was interrupted, keeping buffer fill within limits. Architecturally the "buffer memory + interrupt + rewind + resume-at-location" predecessor of the claimed scheme.
• Potential § 102: pre-AIA § 102(b) (printed publication >1 year before filing). Potentially anticipates claim 1 (buffer memory; medium-side address used to trigger resume) and, more weakly, claim 4. Limiting factor: the interrupt is periodic/idle-driven, not fault-triggered, and it does not disclose reproducing the recorded data and re-encoding it for comparison, so claim 9 (and the "suspend-and-repeat" clause of claim 1) is probably not met. Confidence: medium.

A-2. EP 0 560 600 A2 — "Apparatus and method for preventing data corruption in disk drives from mechanical shock during write operations"

• Applicant: Ministor Peripherals International Ltd.
• Filing/priority: 1992-03-11 · Publication: 1993-09-15
• Description: Detects mechanical shock during a write and takes corrective action to prevent corrupting the just-written region.
• Potential § 102: § 102(b) (1993). Directly relevant to the "first state in which continuity of data may be lost" recited in claim 4, and to the specification's alternative embodiment (shock/vibration sensor in lieu of the buffer-underrun detector). Limiting factor: magnetic disk-drive context; the claim-4 combination with an address memory + synchronizing circuit + retry determination circuit is unlikely to be disclosed. Confidence: medium for claim 4's trigger; low for claims 1/5/9.

A-3. EP 0 974 966 A1 — "Disk recording system"

• Applicant: SANYO ELECTRIC Co., Ltd. (same applicant as US 6,594,213)
• Filing/priority: 1998-07-22 · Publication: 2000-01-26 (JP family: JP 3163064 B2)
• Description: Sanyo's earlier disk-recording system dealing with interruption/restart of recording; the family the present disclosure builds on (cf. the Sanyo "Disk recording device" line, e.g., US 6,584,053).
• Potential § 102: date-sensitive. Published 2000-01-26 — after the 1999-11-22 priority but before the 2000-11-21 U.S. filing, so it may qualify under § 102(a)/(b) only if the critical date is later than asserted, or under § 102(e) via a U.S. counterpart. Note the pre-AIA Hilmer limitation on using the earlier JP priority (1998-07-22) to antedate § 102(e) art. Most relevant to claims 1, 4, 5, 9. Confidence: high relevance; qualification is date-dependent.

A-4. EP 1 098 310 A2 — "Resumption of interrupted recording"

• Applicant: SANYO ELECTRIC Co., Ltd. Filing/priority: 1999-11-05 · Publication: 2001-05-09 (US counterpart: US 6,560,180, "Disk storage device")
• Description: Earlier Sanyo application specifically directed to resuming interrupted recording — the closest-concept art by subject matter.
• Potential § 102: Because its priority (1999-11-05) predates the present patent's 1999-11-22 priority, it can be § 102(e) art through its U.S. counterpart's earlier filing date. Potentially anticipates claims 1, 4, 5 (and 9). Confidence: medium — verifying the U.S. counterpart's filing date is required.

A-5. JP S61-139984 A — "Optical disk device"

• Applicant: Nippon Columbia Co., Ltd. Filed: 1984-12-11 · Published: 1986-06-27
• Description: Early optical-disk device (background; corresponds to Patent Abstracts of Japan vol. 010, no. 338 (P-516)).
• Potential § 102: § 102(b) (1986), but it can support at most generic elements (optical head/encoding/buffering) of claims 1/5; the interruption–address-match–restart core is not disclosed. Confidence: low / background only.

A-6. JP S63-061423 A — "Optical disk device"

• Applicant: Seiko Epson Corp. Filed: 1986-09-01 · Published: 1988-03-17 (PAJ vol. 012, no. 284 (P-740))
• Same assessment as A-5. Confidence: low / background only.

A-7. JP H04-225433 A — "Semaphore synchronization system with canceling function"

• Applicant: Fujitsu Ltd. Filed: 1990-12-27 · Published: 1992-08-14 (PAJ vol. 016, no. 580 (P-1461))
• Description: A cancelable synchronization/semaphore scheme — apparently cited for the synchronization/retry concept.
• Potential § 102: § 102(b) (1992). Possibly relevant to claim 3 (determination of synchronism) and the retry notion in claim 4, but a software semaphore primitive is unlikely to disclose the claimed hardware blocks. Confidence: low.

Non-patent citations (3): the three Patent Abstracts of Japan entries dated 1986-11-15, 1988-08-04, and 1992-12-18 — these are the PAJ abstracts of A-5, A-6, and A-7 respectively, not separate technical disclosures.

3. Provisional second list (List B — US record per FreePatentsOnline)

These foreign documents appeared on the FreePatentsOnline page for 6594213; I could not confirm they sit in the "References Cited" block (they are identical to the foreign references of the sibling US 7,106,675, which shares inventor/filing date but claims a different JP priority). Verify before relying on them:

Note on JP 10-49990: a later document (US 2006/0114779) states that determining the interrupted/resumed write position "in EFM frames" is disclosed in JP H10-49990 and JP 3163064. If that is correct, JP 10-49990 (published 1998-02-20, i.e., § 102(b) relative to the 2000-11-21 filing) is a strong candidate against the interruption/position-tracking aspects of claims 1, 4, 5, 9. (Sourced from the US 2006/0114779 PDF via search; content not independently verified.)

4. Ranking — most relevant prior art

1. EP 0 974 966 A1 and EP 1 098 310 A2 (Sanyo) — same field, same applicant, explicit interrupt-and-resume-of-recording subject matter; closest to claims 1/4/5/9. (EP 1 098 310 A2 qualifies best as § 102(e) art.)
2. EP 0 543 446 A1 (Philips) — the structural ancestor of "buffer memory + interrupt + rewind + resume at matching location" (claim 1).
3. EP 0 560 600 A2 (Ministor) — the shock-triggered recording interrupt (claim 4's "first state"; spec's shock embodiment).
4. JP 10-49990 A / JP 3163064 B2 (per List B) — EFM-frame-based interruption position (claims 1/4/5/9), pending verification.
5. Everything else (JP S61-139984, JP S63-061423, JP H04-225433, KR items) reads as background.

5. What I could not verify (explicit uncertainty)

• The complete, authoritative "References Cited" block on the face of US 6,594,213, including any U.S. patent documents.
• Which (if any) of these references were actually applied by the examiner as § 102 anticipation versus § 103 obviousness versus mere background ("A" documents). A reference printed on a patent's face is not proof it was applied. The file wrapper / Office actions would be needed.
• The actual disclosures of EP 0543446, EP 0560600, EP 0974966, EP 1098310, and the JP/KR items — I have titles and dates only, so the § 102 mappings in § 2–3 are title-and-field-based inferences, not verified element-by-element comparisons.
• List A vs. List B reconciliation (an unresolved discrepancy, not a search-vs-training conflict).
• Omitted in the supplied text and not retrieved: the "U.S. Cl." / "Field of Search" classification evidence that would help narrow the prior-art field.

If you want, I can attempt to pull the front-page image / OCR of US 6,594,213 (or its EP1102261A2 sibling) to lock down the exact examiner-cited set, and then compare each reference element-by-element against claims 1, 4, 5, and 9.

I'll gather the prior-art references associated with this patent before analyzing. Let me run several targeted searches.

Let me pull the actual cited-art lists for this patent and its family members.

Good leads. Let me pull the EPO/EP family search report (which lists the examiner-cited art) and the Google Patents citation list.

Scope note: what I could actually use from the "Prior Art" section

The authoritative Google Patents text I was given includes only part of that page's prior-art material: the "Prior art keywords" field (data, address, recording, circuit, memory) and the "Cited By (24)" list. The "Citations" block (the examiner/applicant-cited references) was truncated out of the fetched text, so I reconstructed what I could by search. Two consequences you should weigh before relying on this:

1. The 24 "Cited By" documents are not prior art. They postdate this patent (mostly 2001–2016) and are third parties citing US 6,594,213 (e.g., US 2003/0016602 Wada, US 2004/0141435 Hitachi-LG, US 2007/0104053 Chen, US 2010/0110855 Philips, US 2016/0191353 MediaTek). Several others are the applicant's own same-family publications (US 2001/0006495, /0006496, /0006498; US 2004/0184374; US 2005/0094525; US 7,106,675; US 7,167,427; US 7,149,167) and are §102(b)/§103 art against themselves, not against this patent.
2. I did not retrieve the full text of any candidate primary reference. Everything below maps claims to references on the strength of titles, dates, assignees, and the abstracts/snippets returned by search. A production §103 analysis would require reading each disclosure. Where I could not verify a reference's critical date, I say so.

Sources: Google Patents US6594213; FPO US6594213; EP1102261A3; US20060114779 (family-citation data); JP2001216721A (family-citation data); EP1102258A3; EPO Global Patent Index EP1102260A2.

1. Legal framework

Analysis under 35 U.S.C. §103 uses the Graham v. John Deere factors as refined by KSR Int'l Co. v. Teleflex Inc. (550 U.S. 398 (2007)): scope/content of the prior art, differences from the claims, PHOSITA level, and objective indicia. Because the priority date is 1999‑11‑22, the pre‑AIA §§102/103 framework applies, but the obviousness standard applied today is KSR: a combination is obvious where the elements were known, the combination is of prior-art elements performing their established functions, and there was an art-recognized reason, design incentive, or finite set of predictable solutions. MPEP 2144.04 (design choice), 2144.06 (art-recognized technique), and 2144.08 (obvious to try) are the operative hooks. Pre-KSR TSM is no longer the sole test, so a "missing teaching to combine" argument is weak if the references are in the same field and address the same problem.

PHOSITA: a B.S.-level engineer with ~2–3 years in optical disc drive firmware/hardware, familiar with the CD‑R "Orange Book Part II," ATIP/sub‑Q absolute-time addressing, CIRC/EFM encoding, PLL pit-clock recovery, and buffer-underrun handling.

2. Candidate reference pool and critical dates

Blunt assessment: the most attractive-looking references — Sanyo's own EP 0 974 966, EP 1 098 310, and the Hayashi "Controller" siblings — are date-barred or same-family and cannot be used as §102/§103 art against this patent. That materially weakens a clean obviousness attack. The strongest qualifying references are US 6,119,201 and US 5,818,801, plus whatever UN/JP/KR art from 1996–1998 the examiner actually cited (which I could not retrieve).

3. Element mapping for the independent claims

4. Specific combinations and the motivation to combine

Combination A — US 6,119,201 (IBM) + US 5,818,801 (Sanyo) → claims 1, 4, 8.
IBM teaches detecting a write-buffer under-run and taking remedial action so an interrupted write on a write-once medium remains usable (padding/link bookkeeping). Sanyo '801 teaches a disc drive that reproduces already-recorded data from the medium through the same servo/decoder chain. Both are in the same field and address the same problem (how to survive an interrupted write on non-erasable media). Motivation: a write-once disc cannot be overwritten, so the only way to resume is to know where you stopped and re-establish position by reading back what you already wrote — that is the established function of each reference, combined for its established purpose (KSR; MPEP 2144.06). Result: claims 1/4/8 elements.

Combination B — A + US 2002/0145959 (Tsukihashi) / US 6,198,707 (Ricoh) → claim 5.
Tsukihashi is directly on point ("temporarily suspending data recording onto a disk"); Ricoh '707 is on point for stopping and restarting within a single track — precisely the "link" problem the patent's background says packet writing solves badly. A POSITA seeking to resume mid-track without packet-writing link blocks would combine these as a matter of design incentive. Claim 5's blocks (ATIP-based address generation, comparators, memories) are all conventional CD‑R hardware.

Combination C — A + B + ordinary skill → claims 2, 3, 6, 7.
Two comparators (claim 2), an AND-gate "synchronization complete" determination (claim 3), a flip-flop/selector state-hold (claim 6), and pit-clock PLL plus clock source switching (claim 7) are each a design choice or art-recognized technique (MPEP 2144.04). Where the invention resides only in arrangement of known circuit blocks to perform known functions, the claims are obvious.

Combination D — the retry/suspend loop (claims 1, 3, 4, 5, 9) as the crux.
This is the only element I could not map to a verified reference. The obviousness argument is KSR "obvious to try" + design incentive: on a write-once medium, a premature restart destroys the disc, so verifying that read-back position and re-encoded buffer position agree simultaneously before firing the laser is the predictable, near-mandatory safeguard. Retrying acquisition until two independent position signals agree is standard error-recovery practice (servo re-acquisition, sync hunt). The patent's own framing supports this: the specification states the retry guards against "an external disturbance [that] occurs for one reason or another (e.g., the application of an external impact)," i.e., it is presented as robustness engineering, not a new mechanism. Under KSR, "a finite number of identified, predictable solutions" with a reasonable expectation of success supports obviousness.

Note also claim 1's "at least one of" alternative — restart on either the medium-side or buffer-side match. That breadth reduces the elements that must be taught, making claim 1 easier to invalidate than claim 4 (which requires the retry determination circuit) or claim 5 (which requires simultaneous match signals). Claim 1 also presents a §112(b) alternative-claiming problem — the same language that makes it vulnerable under §103.

5. Counterarguments I would expect, and how they fare

• "No teaching to combine / different problems." Weak here: the references are all CD‑R under-run/resume art sharing one field and one problem, which KSR treats as sufficient.
• "Packet writing taught away." This is the patent's best argument and it is still weak. The background disparages packet writing (link blocks, CD‑ROM/Orange Book II incompatibility, no CD‑DA support) — but that establishes the known alternative, i.e., a recognized need that supplies motivation, and packet-writing's shortcomings are not a teaching away from buffer-under-run protection; they are a teaching away from packet writing. A teaching-away argument requires the prior art to criticize, discredit, or discourage the claimed solution — not merely a favored alternative.
• Objective indicia. There is real-world evidence of rapid, parallel commercialization in this exact space around 2000–2001 (Sanyo "BURN-Proof," Ricoh "JustLink," Philips "Seamless Link," Yamaha "SafeBurn"). I have not verified these attributions in this session beyond general knowledge, so treat with caution — but if accurate, simultaneous independent development by multiple competitors is evidence toward obviousness, not away from it. Any commercial-success argument also suffers a nexus problem: the patent is one of a large same-family cluster (US 7,106,675 / 7,167,427 / 7,149,167 all share the 1999‑11‑22 priority), so the success cannot be attributed to this claim set specifically.

6. Bottom line

• §102: I found no single verified reference disclosing the whole of claim 1 (in particular the read-back-synchronize-restart sequence with the premature-match suspension). Anticipation looks untenable on the record available to me. US 6,119,201 comes closest on the under-run handling but appears to lack the read-back synchronization and the retry loop.
• §103: Claims 1, 4, 5, 8 and 9 are reasonably attackable as combinations of (i) buffer-under-run interrupt/resume art (US 6,119,201; US 5,818,801), (ii) mid-track stop/restart art (US 6,198,707; US 2002/0145959), with the retry/simultaneous-match verification supplied by the write-once imperative plus routine error-recovery design (KSR "obvious to try"). Claims 2, 3, 6 and 7 fall to design choice and art-recognized techniques once the independent claims fall.
• Biggest risk to the attack: the two most on-point Sanyo references (EP 0 974 966, EP 1 098 310) are date-barred, and I could not obtain the examiner's actual "Citations" list. A reliable §103 opinion needs (a) the original citation list from the file wrapper, and (b) full-text review of US 6,119,201, US 5,818,801, US 6,198,707, and the 1996–1998 JP/KR references. I could not verify the filing/priority dates of US 6,198,707 or US 2002/0145959, and their §102 status is conditional on pre‑1999‑11‑22 US filings.

If you want, I can attempt to retrieve the examiner's citation list from the USPTO PatentCenter/public PAIR record for application 09/717,777, or pull the full text of US 6,119,201 and US 5,818,801 to firm up the element mapping.