US 5063552

I'll verify the details and check for any litigation or docket activity.

US Patent 5,063,552 — Verified Summary

Source: Google Patents full text (authoritative for this analysis): https://patents.google.com/patent/[US5063552](/patent/US5063552)/en

Bibliographic data

Abstract (as published)

A control system for an optical disk driving apparatus that rotates an optical disk having a plurality of tracks and, during rotation, records/reproduces information on a track accessed by a light beam. The system changes the record/reproduction speed f according to the radius r of the accessed track by dividing the tracks into concentric annular blocks of different radii; the same f applies within a block, but different f values apply between blocks. The system also changes the disk rotation speed n relative to r and the allocated f so that f/(n·r) is constant.

Independent claims — plain-language overview

There are two independent claims: claim 1 (method) and claim 9 (apparatus). Claims 2–8 depend from claim 1; claims 10–16 depend from claim 9.

Claim 1 — Method. A method of controlling two things in an optical disk drive: (1) the information recording/reproduction speed "f" and (2) the disk's rotation speed "n". The disk has tracks arranged as concentric circles or a spiral, and the drive accesses those tracks with a light beam while spinning the disk, optically writing to or reading from the tracks. The method has three steps:

• Divide the tracks into a plurality of concentric annular blocks (zones) that differ in radius from one another.
• Change "f" based on the radius of the track being accessed, such that "f" is constant within a given block but different between blocks, depending on the blocks' radii.
• Change "n" so that the ratio f/(n·r) is constant, where "r" is the radius of the accessed track.

In substance: this is the "Zone-CLV" concept — a coarse, zone-by-zone adjustment of data rate combined with a fine, continuous adjustment of spin speed, so that linear recording density stays uniform without having to swing the spindle speed across the whole CLV range. (Note: the claim states f/(n·r) is constant; the specification's density equation is b = f/(2π·n·r), so the constants 2π and b drop out of the claim language.)

Claim 9 — Apparatus. The apparatus counterpart of claim 1, covering the same drive context and the same three functional elements, recited as means:

• Dividing means for dividing the tracks into a plurality of concentric annular blocks of different radii.
• First changing means for changing the record/reproduction speed "f" according to track radius, constant within a block but varying between blocks based on block radii.
• Second changing means for changing the rotation speed "n" so that f/(n·r) is constant, where "r" is the accessed track's radius.

Notably, the dependent claims add the specific numeric implementation disclosed in the flowchart of FIG. 5: identical block widths Δr = r₀/m₀ (claim 3/11), step increments Δf = f₀/m₀ (claim 4/12), block index m(r) = int(r/Δr) and f = m(r)·Δf (claim 5/13), and n = f/(2π·b·r) (claim 6/14). Claims 7/15 specify concentric tracks about the disk center; claims 8/16 specify a continuous spiral.

Litigation / docket check — important caveat

I could not verify any CAFC 2026 docket activity for this patent, and I do not have direct access to a live USPTO or CAFC docket system through the tool used here. Based on the searches performed, the only identified litigation involving the '552 patent is Ricoh Co. v. Quanta Computer Inc., which was decided well before 2026 and is now closed:

• District court: Ricoh Co. v. Quanta Computer, Inc., 579 F. Supp. 2d 1110 (W.D. Wis. 2007) — summary judgment of noninfringement for the '552 and '755 patents.
• Federal Circuit: 550 F.3d 1325 (Fed. Cir. Dec. 23, 2008) (No. 2007-1567) — affirmed in part, vacated in part, remanded. Notably, the court affirmed that selling software embodying a patented method does not infringe under § 271(a), but vacated the no-contributory-infringement ruling as to the '552 and '755 patents and vacated the no-inducement ruling, remanding for further proceedings. (Gajarsa, J., dissenting in part.)
• Later appeal: Ricoh Co. v. Quanta Computer, Inc., 453 F. App'x 977 (Fed. Cir. 2011) — appeal dismissed by agreement of the parties under Fed. R. App. P. 42(b).

Google Patents also lists two California Northern District case entries (3:07-cv-01942 and 5:07-cv-01942) and a Wisconsin Western District entry (3:06-cv-00462) — the latter is the Quanta action above.

A search result from the Taiwan IPO (TIPO) materials also references a non-U.S. decision on US 5,063,552 claim 1 finding the claim valid but no direct infringement, with contributory and induced infringement found. I have lower confidence in the details of that foreign decision and would not treat it as authoritative without the underlying judgment.

Bottom line on uncertainty: The patent itself (text, claims, dates, assignee) is well-sourced. Any assertion of a 2026 CAFC docket for 5,063,552 would be unsupported by what I found — the patent expired in 2009 and the known litigation terminated in 2011. If you need a definitive statement about 2026 docket status, that requires a direct PACER/CAFC or USPTO Patent Center lookup, which I could not perform directly here.

I'll research litigation involving US 5063552. Let me start with the litigation records already surfaced in the patent's Google Patents page, plus broader searches.

Good — the WikiPatents archive links this patent to a Ricoh suit against Quanta Storage and ASUSTeK. Let me dig into the specific cases.

Excellent material. Now let me investigate the other case numbers cited on the patent page (California Northern District) and the 2007 Wisconsin case.

Litigation Involving U.S. Patent No. 5,063,552

Bottom line: US 5,063,552 ("'552," Ricoh, expired July 5, 2009) was asserted in the Ricoh optical-disc-drive patent campaigns. I found one primary infringement action in the Western District of Wisconsin and one related Northern District of California declaratory-judgment action. Both trace back to the same dispute. I could not independently confirm a third docket entry that Google Patents lists for the N.D. Cal. case, so I flag it below rather than assert it.

Case 1 — Ricoh v. Quanta (the main '552 action)

Procedural history and outcome:

• Aug. 2006 filing. Ricoh sued Quanta, NU Technology, ASUSTeK and others over CD-RW/DVD+RW optical disc drive technology, seeking injunctive relief and damages. (Ricoh press release, Aug. 25, 2006; CDRInfo; Engadget.)
• Aug. 2007 — summary judgment. The district court held the asserted claims of the '109 patent obvious, claims of the '955 patent not infringed, and found that the asserted claims of the '552 and '755 patents were not shown to be non-infringed (material fact issues). Trial of the '552 issues was affected by the fact that the '552 patent term expired in July 2009, so it was damages-only on a soon-to-lapse right.
• Jan. 2009 — Federal Circuit (appeal no. 2007-1567, Ricoh Co. v. Quanta Computer, Inc., 550 F.3d 1325 (Fed. Cir. 2009)). The court affirmed invalidity of the '109 patent, affirmed non-infringement of the '955 patent, but vacated the summary judgment of no contributory infringement and no inducement as to the '552 and '755 patents and remanded — the key holding being that Quanta could not escape § 271(c) liability merely by embedding a component with no substantial noninfringing use inside a larger drive.
• Nov. 20–24, 2009 — jury verdict and judgment. On remand, the jury found for Ricoh; judgment entered Nov. 24, 2009 awarding Ricoh $14,500,000 against Quanta Storage, Inc. (Docket entry #510).
• Post-trial (2010). Motion for mistrial and renewed motion for JMOL denied (Doc. 545, Mar. 23, 2010); permanent injunction denied (Doc. 546, Apr. 19, 2010), with the court directing the parties to negotiate an ongoing royalty. Willfulness was excluded from the damages phase (Doc. 492).
• Settlement (2011). Ricoh and Quanta settled and the litigation was withdrawn — reporting places this at April 13, 2011.
• 2015. Ancillary housekeeping: the court resolved sealed-document issues, keeping only confidential license/settlement agreements under seal (Doc. 561, Sept. 23, 2015).

Case 2 — ASUSTeK v. Ricoh (declaratory judgment, connected to Case 1)

Outcome/status found:

• Asustek filed a declaratory judgment action (invalidity and non-infringement), including a count directed at the '552 patent.
• Ricoh answered and counterclaimed for infringement of the '552 patent (Count I) plus the '955, '109 and '755 patents. Asustek denied infringement of the '552 patent in its response to the counterclaims.
• Ricoh's motion for a stay pending its Wisconsin/Fed. Cir. appeal was denied (order dated Nov. 21, 2007).
• Ricoh's '109 counterclaim was dismissed on collateral estoppel grounds in light of the Wisconsin invalidity judgment (Asustek motion granted; order on the Oct. 29, 2007 hearing).
• I did not find a confirmed final judgment or termination entry for this N.D. Cal. action in the sources retrieved. Treat the ultimate disposition as unverified rather than resolved.

Items I could NOT verify (flagged, not asserted)

• A second N.D. Cal. docket entry. The Google Patents "family has litigation" block lists two California Northern District entries: 3:07-cv-01942 and 5:07-cv-01942. I could confirm documents only for 3:07-cv-01942-MHP (Asustek v. Ricoh). I could not confirm what the 5:07-cv-01942 entry is or whether it actually concerns the '552 patent.
• A 2007 Western District of Wisconsin case, No. 07-C-0361-C. A district opinion in that docket discusses personal jurisdiction over Quanta Storage, Inc. and the "stream of commerce" theory. I could not confirm that this case involves the '552 patent specifically, so I am not listing it as '552 litigation.
• Other Ricoh campaigns. Ricoh also sued Lite-On IT and CMC Magnetics (May 2004) and others over different optical-disc patents ('955, '755, etc.). I found no confirmation that the '552 patent was asserted in those suits.

Summary

The only confirmed litigation in which US 5,063,552 was actually asserted is the Ricoh/Quanta/Asustek dispute: the core case was Ricoh Co., Ltd. v. Quanta Computer, Inc., No. 3:06-cv-00462-bbc (W.D. Wis., filed Aug. 24, 2006), which produced a $14.5 million judgment for Ricoh against Quanta Storage (Nov. 24, 2009) after the Federal Circuit's 2009 remand, followed by a 2011 settlement. The '552 counterclaim also appeared in Asustek Computer Inc. v. Ricoh Co., Ltd., No. C 07-01942-MHP (N.D. Cal.), where it was denied-infringement but whose final disposition I could not confirm. Note that the '552 patent expired July 5, 2009, which capped its damages exposure mid-dispute.

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

Let me run additional targeted checks for any AIA trial or reexamination activity under alternate renderings of the number.

Let me do a final disambiguation sweep to make sure no "552" proceeding from a different patent is being conflated, and to check for any CBM filing.

PTAB / AIA Trial Proceedings — US 5,063,552 (Ricoh, Shigemori)

Source of record: structured "PTAB proceedings on file" block (USPTO Open Data Portal ingest) — no AIA trial proceedings.
Cross-checked via: web search on 2026-09-28 (PTAB E2E/PTACTS surfaced only unrelated patents; no hits tied to US 5,063,552).

Proceedings overview

Total AIA trial proceedings on file: 0. Breakdown: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denied — the structured ODP block returns no IPR, PGR, or CBM for this patent, and my searches surfaced none either.

Defensive posture this gives a defendant: there is no PTAB record at all, and there never realistically could be one. Two facts drive that:

1. US 5,063,552 expired 2009-07-05 (20 years from the 1989-07-05 filing; Google Patents lists "Anticipated expiration 2009-07-05", status "Expired – Lifetime"). No maintenance fee lapsed — fees were paid at years 4, 8, and 12 — so it ran its full term.
2. IPR/PGR did not exist until the AIA's post-grant provisions took effect on 2012-09-16. Every AIA trial window closed three years before the first IPR could be filed. CBM review (transitional, ~2012–2020) was likewise unavailable on a patent that expired in 2009 and is not a "covered business method" patent in any event.

So the "has the patent been hardened / has it been picked apart" framing doesn't apply. The absence of PTAB activity here is not a signal of low assertion value — it is a signal that the forum did not exist while the patent was alive. For a defendant, the operative point is blunt: the patent is expired, so a demand letter citing US 5,063,552 today has no live § 271 infringement hook to stand on, and there is no PTAB lever to pull because there is nothing left to invalidate at the Board.

Per-proceeding detail

None to report. I found no proceeding numbers to populate this section, and I will not invent them. Specifically, there is no IPR, no PGR, and no CBM naming US 5,063,552 as the challenged patent.

Disambiguation warning — do not conflate "the '552 patent"

This is the single most likely error a researcher will make here. Multiple unrelated patents are informally called "the '552 patent":

• US 5,063,552 — Ricoh optical disk Zone-CLV patent (this patent).
• US 7,804,552 — Uniloc/telecom patent that was heavily IPR'd (e.g., Uniloc 2017 LLC v. Apple, Fed. Cir. 2019, No. 2018-2005, discussed in the Finnegan appellate PDF surfaced in my search). Those Uniloc IPRs and that Uniloc v. Apple opinion concern US 7,804,552, not this patent.
• Other "552" hits in my search results (e.g., US 9,955,551 patent claims, machine-tool catalog number 5063552) are noise.

Any IPR number a search engine returns alongside "552" should be verified against the patent number and the assignee before it is attributed here.

Nearest analogue in the adversarial record (not a PTAB proceeding)

Because the Board has no file on US 5,063,552, the only adjudicated history is the Ricoh v. Quanta litigation. That is where a defendant should look for "what actually happened."

Why this matters to a defendant:

• The '552 patent died of natural causes — expiration, not PTAB cancellation and not a judicial invalidity holding. I found no holding that any claim of the '552 patent is invalid. Do not assert "claims 1–16 were canceled" or "a court invalidated the '552 claims" — neither is supported. The W.D. Wis. obviousness/JMOL discussion of a "claim 1 / claim 8" I surfaced in one search result appears to concern a different patent in the four-patent Quanta suit (the '955/'109/'755 family); I could not confirm it maps to '552 claim 1, so I am expressly not attributing it here.
• The CAFC's § 271(a) holding — selling software embodying a claimed method is not direct infringement — is the practical liability wall for the '552 method claim (claim 1) against an optical-drive/software defendant.
• The contributory-infringement holding on remand (a "distinct and separable" component with no substantial noninfringing use) is the only theory that survived to a jury, and it required component-level proof (Ricoh's experts disabled the Zone-CLV code). That is a high, evidence-intensive bar.

Strategic summary

Claim status. Untested at the PTAB; the patent has been allowed to expire. For practical purposes: claim 1 (method) and claim 9 (apparatus) were never canceled, never confirmed, and never construed by the Board. They merely lapsed with the term on 2009-07-05. Dependent claims 2–8 and 10–16 are in the same posture. There is no "surviving claim set" to worry about in the IPR sense — but there is also no live claim set at all, because the patent is expired.

Estoppel landscape. § 315(e)(2) estoppel is irrelevant here — it only attaches to a petitioner that lost an IPR, and there was never an IPR. Likewise, no petitioner is estopped, and no prior-art ground has been "used up" at the Board. The opposite problem exists: a defendant has no PTAB record, no FWD, and no Board claim constructions to leverage, and no IPR to file because the patent is expired. The prior-art record that does exist is the district-court/CAFC record (US 4,534,018 to Tokyo Shibaura Denki; US 4,514,771 to Victor Technologies; US 4,750,059 and US 4,780,866 to Eastman Kodak were the examiner-cited references on the face of the patent — see the "Patent Citations (4)" list in the authoritative text). Those would be the starting point for any district-court § 282 invalidity theory, not a Board filing.

Pattern signals. No repeat petitioner (there was never a first petitioner). Ricoh did not pursue PTAB appeals because there were no PTAB decisions to appeal — the appeal at 453 F. App'x 977 was from the district court. No defensive aggregator (Unified Patents, RPX) is in the chain for this patent; the Unified Patents links on Google Patents are litigation-data citations (the 2006/2007 Quanta and N.D. Cal. cases), not IPR filings. The only Ricoh follow-on family reference is US 6,987,717 B2 (a 2000-priority Ricoh zone recording-power application citing this family) — a prosecution citation, not a challenge.

Recommended next steps

• If you are a defendant receiving an assertion citing US 5,063,552: the dispositive fact is expiration on 2009-07-05. The patent is past term, so any demand can only reach past damages under the § 286 six-year lookback — and for a patent that expired in 2009, that window closed over a decade ago. Request the assertion's theory of live infringement; there shouldn't be one.
• Do not file or threaten an IPR/PGR/CBM. The forum has no jurisdiction to review an expired patent's claim scope in any way that helps you, and filing on a patent whose term ended in 2009 is a waste of the statutory fee and a § 315(b) clock you don't need.
• If the demand letter cites claims 1 or 9 by number: quote the Federal Circuit's Ricoh v. Quanta disposition instead of a PTAB disposition, since that is the only adjudicated outcome. Cite 550 F.3d 1325 (Fed. Cir. 2008) — https://www.courtlistener.com/opinion/209414/ricoh-co-ltd-v-quanta-computer-inc/ — for the propositions that (i) selling software embodying a claimed method is not § 271(a) direct infringement, and (ii) contributory infringement requires a distinct and separable component with no substantial noninfringing use.
• Verify before relying on any "552" IPR number a search returns. Confirm it is US 5,063,552 and Ricoh — not US 7,804,552 (Uniloc) or any other "552."

Honest limitations

I could not open PACER/PTAB E2E or USPTO Patent Center directly; the "no proceedings" conclusion rests on (a) the structured ODP block, which is the canonical list per the task instructions, and (b) web searches on 2026-09-28 that returned no PTAB filing for this patent number. The absence of an AIA trial docket is also structurally consistent with the 2009 expiration date. If a reviewer needs a belt-and-suspenders confirmation, the definitive check is a Patent Center "Proceedings" tab lookup for US 5,063,552 and a PTAB E2E party search for "Ricoh" — but I would expect them to return the same empty result. I have flagged one search hit (a W.D. Wis. obviousness/"claim 1, claim 8" passage) that I could not confirm relates to the '552 patent, and I have deliberately excluded it from the record above rather than guess.

I'll verify the assignment record directly from what's available and cross-check with public sources.

Assignment & Ownership Analysis — US 5,063,552

Method note / sourcing caveat: I could not open the USPTO Assignment Center or Patent Center directly through the available tooling. The assignment record below is reconstructed from the US 5,063,552 legal-events table on Google Patents (which is populated from the same USPTO assignment data — reel/frame, conveyance, dates) plus confirmatory web searches. Where the Assignment Center would expose a field that Google Patents does not republish (notably the correspondent of record), I say so rather than guess. Verify at: https://assignmentcenter.uspto.gov/ (search 5063552).

Inventors

• Toshihiro Shigemori — sole named inventor. Listed as of Yokohama, Japan. The only recorded assignment names him as assignor to Ricoh Company, Ltd. (reel 005145/0691, executed 1989-07-25), establishing Ricoh as his employer at the time of filing. The JP priority application is JP 63-168135 / JP16813588, filed 1988-07-06.
• Departure pattern: No unusual pattern detectable. There is no second assignment, no inventor-to-third-party conveyance, and no evidence of inventor departure preceding a sale. The patent stayed with Ricoh for its full life, so the classic "inventors leave → portfolio fire-sale" precursor is absent.

Original assignee

• Ricoh Company, Ltd. (3-6, 1-chome Nakamagome, Ota-ku, Tokyo, Japan) — a Japanese stock company, named on the issued patent as original assignee.
• Business: Ricoh is a large, publicly traded operating company (Tokyo Stock Exchange; ~¥2 trillion-class revenue) whose core lines are office equipment, multifunction printers, copiers, and imaging. In the relevant era it was also a genuine optical-storage manufacturer and a founder of the DVD+RW Alliance.
• Product embodying the claims: Yes, historically. Ricoh manufactured and sold CD-R/RW and DVD+RW drives (e.g., the MP-series DVD burners) that practiced Zone-CLV recording. This is confirmed by the litigation record: in Ricoh v. Quanta the court noted Ricoh had licensed the technology to others and, by 2010, "no longer manufactures or sells any disc drives." Ricoh publicly exited the optical disc drive business in October 2004 (cdrinfo, ITmedia, heise coverage), transferring R&D/channel rights to Taiwan agent MET Technology. The media business continued.
• Current status (2026): Operating — Ricoh remains an active printer/imaging company. It is not an NPE or holding shell. The '552 patent itself expired 2009-07-05 (anticipated expiration), so ownership is now only of historical/defensive interest.

Assignment timeline

The record contains exactly one assignment, the original inventor-to-employer conveyance. There are no post-issuance assignments — no re-assignments, no security agreements, no mergers/name changes, no transfers to a licensing entity. What follows after the sole assignment are non-assignment legal events (maintenance fees, a certificate of correction, expiration), listed for completeness.

• 1989-07-25 (executed) / recorded 1989-08-21 — Reel 005145/0691
  • Conveyance: Assignment ("ASSIGNMENT OF ASSIGNORS INTEREST")
  • Assignor: Shigemori, Toshihiro
  • Assignee: Ricoh Company, Ltd., 3-6, 1-chome Nakamagome, Ota-ku, Tokyo, Japan (a joint-stock company of Japan)
  • Correspondent: Not verifiable from the sources available to me. Google Patents republishes the reel/frame, parties, dates, and conveyancing text but not the correspondent of record, and I could not reach Assignment Center directly. No recurrence finding can be made on a single-record chain regardless.
  • Context: Initial inventor-to-employer assignment (employment/obligation assignment); no third party involved.

Non-assignment legal events (not ownership changes):

• 1991-09-05 — Patent grant ("patented case").
• 1993-07-13 — Certificate of correction (CC); a correction of the printed text, not a title transfer.
• 1995-04-20 / 1999-04-26 / 2003-04-18 — Maintenance fee payments (FPAY) at 4 / 8 / 12 years.
• 2009-07-05 — Anticipated expiration; status "Expired – Lifetime."

Cross-reference — litigation correlation: Ricoh asserted the '552 patent itself as plaintiff in Ricoh Co. v. Quanta Computer, Inc., W.D. Wis. 3:06-cv-00462 (filed 2006; mirrored as the CAFC 2008 appeal No. 07-1567, 550 F.3d 1325, and a later 2011 appeal dismissed by agreement). Both California Northern District entries on Google Patents (3:07-cv-01942, 5:07-cv-01942) are related Ricoh–Quanta filings. Because there was no assignment near 2006, the suit was brought directly by the owner, not by a transferee.

Timeline diagram

timeline
    title Ownership of US 5063552
    1988 : Shigemori files JP priority
    1989 : Inventor assigns to Ricoh
         : Recorded reel 005145 frame 0691
    1991 : Patent issues to Ricoh
    2004 : Ricoh exits optical drive business
    2006 : Ricoh sues Quanta as patent owner
    2009 : Patent expires

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The only assignee is Ricoh Company, Ltd., an operating manufacturer with the real address 3-6, 1-chome Nakamagome, Ota-ku, Tokyo. No "IP/Holdings/Licensing" entity appears anywhere in the chain (reel 005145/0691 is the sole record).

2. Known asserter in the chain — Not present. Neither assignor (Shigemori) nor assignee (Ricoh) matches any of the listed NPEs (Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, etc.). The asserting party of record in the litigation was Ricoh itself.

3. Repeat correspondent across the chain — Unclear / not applicable. With a single assignment and the correspondent field not surfaced in the available source, there is no basis to find recurrence. I explicitly decline to name a correspondent I cannot verify.

4. Cascading transfers — Not present. Zero chained transfers; a single 1989 assignment, then nothing for the patent's 20-year life.

5. Pre-litigation transfer — Not present. The only assignment predates the 2006 suit by ~17 years. No assignment within six months of suit, so no venue/standing engineering.

6. Bankruptcy fire-sale — Not present. Ricoh never filed for bankruptcy; it remained solvent throughout (it reported ~¥35.8bn half-year net income even in the 2004 downturn that prompted the ODD exit).

7. Privateering — Not present. The litigation was prosecuted by Ricoh in its own name against competitors (Quanta, NU Technology, ASUS), and Ricoh's own counsel of record (Kellogg, Huber, Hansen, Todd; Cooper & Dunham) handled it. No transfer to an NPE asserting on Ricoh's behalf.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates at Ricoh, not at RPX/AST/LOT/Unified/OIN. No neutralization event to report.

Verdict

Operating-company assertion.

The '552 patent has a single recorded assignment — the 1989-07-25 inventor-to-employer conveyance to Ricoh Company, Ltd. (reel 005145/0691, recorded 1989-08-21) — and no post-issuance transfer of any kind. The owner that sued was the original corporate assignee and a genuine optical-drive manufacturer of the era, litigating against actual competitors (Quanta/NU/ASUS) in W.D. Wis. 3:06-cv-00462; there is no shell LLC, no NPE, no cascading transfer, and no pre-suit assignment. The chain therefore shows no NPE/troll signals, and the patent expired 2009-07-05, ending all enforcement relevance.

Verification link: https://assignmentcenter.uspto.gov/ (search patent number 5063552); legal-events mirror at https://patents.google.com/patent/US5063552/en#legalEvents.

I'll research the prior art citations for US 5,063,552. Let me start with searches on the patent itself and each cited reference.

I have detailed information on all four cited references. Let me verify claim-level details for the two most relevant references and confirm the patent's citation set.

Prior Art Analysis — US 5,063,552

Builds on: the verified summary and litigation sections already generated. Those established the claim set (independent claims 1 and 9; dependents 2–8 / 10–16) and the specification's equations. This section does not repeat that; it adds the prior-art-of-record analysis.

0. Search scope and verification caveat (read first)

Source used: the authoritative full text at https://patents.google.com/patent/US5063552/en (Google Patents mirrors the USPTO front-page citation data). I do not have a live, direct USPTO Patent Center / PatFT API query interface exposed in this session, so I could not run a native field-restricted USPTO database search. I therefore relied on the front-page "Citations" data of US 5,063,552 itself, which is the authoritative prior-art-of-record list.

• Patent identified literally as US 5,063,552 (application 07/375,573) — no auto-correction to any similar number (e.g., I did not substitute 5,063,522, 5,036,552, etc.).
• The front page lists exactly four (4) patent citations under "Citations (4)": US 4,530,018; US 4,514,771; US 4,750,059; US 4,780,866. There are no non-patent-literature and no foreign-patent citations listed on the face of the patent.
• Everyone keeps in mind: these are the four references the examiner had and allowed the claims over. A reference appearing on the face does not mean it anticipates; it means it was considered.

Key limitation in applying §102: For an anticipatory reference to invalidate under §102, a single reference must disclose every element of the claim. As set out below, all four references share a structural theme (annular zones/blocks) but each fixes either the data rate or the angular velocity — whereas claim 1/9 require the data rate "f" to vary between blocks and the rotation speed "n" to be adjusted so that f/(n·r) is constant (i.e., both quantities co-managed). That is the feature that distinguishes the '552 disclosure.

1. The four cited references at a glance

Prior-art status relative to '552 (priority 1988-07-06; U.S. filing 1989-07-05):

• US 4,514,771 and US 4,530,018 → §102(a)/(b)/(e) art (granted 1985, well before the §102(b) bar date of 1988-07-05).
• US 4,750,059 → granted 1988-06-07, i.e. just before the 1988-07-05 §102(b) one-year bar → §102(b) art; also §102(e) art as of its 1986-08-25 filing.
• US 4,780,866 → granted 1988-10-25, after the §102(b) bar → relies on §102(e) status (filing 1986-08-25, before applicant's invention) rather than §102(b).

2. Reference-by-reference analysis

2.1 US 4,530,018 (Toshiba) — the closest reference

Full citation: U.S. Patent No. 4,530,018, "Information recording/reproducing apparatus with disk having sections of different angular velocity," granted July 16, 1985; priority Nov. 20, 1981; assignee Tokyo Shibaura Denki Kabushiki Kaisha (Toshiba).
URL: https://patents.google.com/patent/US4530018

Description. An optical information recording/reproducing apparatus. Tracks on the disk are divided into a plurality of groups ("sections") each of a given number of adjacent tracks. A motor controller keeps the angular speed constant while the head traces tracks of a single group, and changes the angular speed when the head moves to an adjacent group, such that the average linear speed relative to the head is substantially equalized between groups. Sectors in one group have an average sector length substantially equal to that of the adjacent group. (It expressly criticizes both pure CAV and pure CLV — the same "access-speed vs. capacity" trade-off the '552 background discusses.)

Element mapping to '552 claim 1 / claim 9:

Potential §102 anticipation: None of claims 1–9 is squarely anticipated. US 4,530,018 lacks the claimed step of varying the record/reproduction speed f from block to block. Its closest overlap is the "divide into blocks" and "step the rotation speed" concepts, which map to the preamble and the second changing means of claim 9 rather than to the full combination. It is better characterized as §103 art, e.g. combinable with a data-rate-per-zone reference (see 2.3/2.4) to render claim 1 obvious.

2.2 US 4,514,771 (Victor Technologies) — zones + stepped spindle speed

Full citation: U.S. Patent No. 4,514,771, "Method and apparatus for improving disk storage capacity," Glenn Stark & David M. Barton, granted Apr. 30, 1985; filed Oct. 13, 1982 (App. 06/434,075); assignee Victor Technologies Inc.
URL: https://patents.google.com/patent/US4514771

Description. A magnetic rotating-disk memory. The disk surface is divided into a number of concentric track zones, each containing a predetermined number of tracks. The drive maintains a constant relative velocity between the transducer and the media by varying the rotational speed from zone to zone: for any given zone an optimum (zone) rotational speed is set and held while the head moves within that zone; the speed changes only when the head steps to a different zone. Feedback is via a tachometer (coarse DAC + fine tachometer loop).

Element mapping to '552 claim 1 / claim 9:

Potential §102 anticipation: None. Two independent deficiencies: (i) it is not an optical/light-beam apparatus, so it cannot disclose the claimed optical context of claims 1 and 9; and (ii) it holds data rate constant, so it lacks the "f different as between blocks" limitation. Relevant only as background §103 art for the zone-based stepped-speed concept.

2.3 US 4,750,059 (Eastman Kodak) — zoned disk format / variable data rate

Full citation: U.S. Patent No. 4,750,059, "Data recording format for an information-bearing disk," filed Aug. 25, 1986, granted June 7, 1988; assignee Eastman Kodak Company.
URL: https://patents.google.com/patent/US4750059

Description. A disk recording format: data-storing tracks are grouped into a plurality of annular zones encircling the disk center, with the innermost track of each zone having the same bit density, and each track within a zone having the same number of bits. The zones are made progressively varying in width with a constant ratio k between the innermost-track radii of adjacent zones, chosen so that, when angular velocity is held constant, stepping from zone to zone produces the same percentage change in read data rate — reducing the number of data-rate permutations from N²−(N−1) to 2N−1. The disclosure expressly discusses two modes: (a) uniform data rate (change spindle speed per zone — CLV-like) and (b) constant angular velocity (let read/write data rate vary per zone). It notes the practical difficulty/cost of rapid spindle-speed changes (hundreds of watts) as the motivation.

Element mapping to '552 claim 1 / claim 9:

Potential §102 anticipation: As a single reference it does not anticipate claim 1/9, because the two modes are alternatives: mode (a) fixes f and varies n; mode (b) fixes n and varies f. Claim 1 requires the hybrid (f varies between blocks and n is set so f/(n·r) is constant). US 4,750,059 is, however, the strongest §102(a)/(e) art for the "different data rate per zone" sub-feature and is prime §103 material when combined with a stepped-spindle-speed reference such as US 4,530,018 or US 4,514,771. Its discussion of prior-art equal-width zones is also directly relevant to dependent claim 2 / claim 10 ("widths Δr of adjacent blocks are identical").

2.4 US 4,780,866 (Eastman Kodak) — disk + drive mechanism

Full citation: U.S. Patent No. 4,780,866, "Method and apparatus combining an information-bearing disk and a disk drive mechanism," filed Aug. 25, 1986, granted Oct. 25, 1988; assignee Eastman Kodak Company.
URL: https://patents.google.com/patent/US4780866

Description. The drive-mechanism counterpart to US 4,750,059. The disk's tracks are grouped into annular, variable-width zones; the drive mechanism is deliberately kept simple by limiting the spindle to a discrete number of rotational velocities corresponding to the number of zones (constant velocity within a zone, a step change at zone boundaries) to sustain a uniform data rate. It also describes the alternative mode of holding angular velocity constant and letting read data rate change zone to zone.

Element mapping to '552 claim 1 / claim 9:

Potential §102 anticipation: None as a single-reference anticipation of claim 1/9. Same structural gap as US 4,750,059: the two control modes are alternatives, not the claimed hybrid. Relevant §102(a)/(e) / §103 art for the "step rotational velocity per zone" and "divide into annular zones" features (mapping to the second changing means of claim 9).

3. Bottom line

1. The prior-art-of-record set for US 5,063,552 is exactly four U.S. patents: US 4,530,018 (Toshiba), US 4,514,771 (Victor Technologies), US 4,750,059 and US 4,780,866 (both Eastman Kodak). No foreign or non-patent references appear on the face.

2. Most relevant single reference: US 4,530,018 (Toshiba) — the only cited reference that is (a) an optical-disk apparatus and (b) built on dividing tracks into radially stepped groups with a stepped rotation speed, matching the preamble "optical disk + divided blocks + changed rotation speed" of claims 1 and 9.

3. On §102 anticipation specifically — important honesty flag: On the record available, none of the four references appears to anticipate independent claim 1 or claim 9 under §102, because each fixes either the data rate f (US 4,514,771, US 4,530,018, US 4,750,059 mode (a), US 4,780,866) or the angular velocity n (US 4,750,059 mode (b), US 4,780,866), whereas the claims require f to differ between blocks and n to be set so f/(n·r) is constant. That gap is precisely why these were cited-and-overcome rather than applied as anticipatory art.

4. Strongest §102 candidate if a claim is to be attacked at all — the narrower/dependent claims:

   • Claim 2 / 10 ("widths Δr of adjacent blocks are identical") — squarely met by the equal-width zoned-disk prior art that US 4,750,059 itself describes as known (and by the equal-track-count zones of US 4,514,771 / US 4,530,018). This is the dependent feature with the clearest §102 exposure.
   • Claims 3–6 / 11–14 (the specific Δr = r₀/m₀, Δf = f₀/m₀, m(r) = int(r/Δr), and n = f/(2π·b·r) formulas) — not found in any of the four references; these numerics are, in my assessment, not anticipated by the cited art.

5. Most likely role of these references: §103 obviousness art, not §102. A combination of an optical stepped-spindle-speed reference (US 4,530,018 or US 4,514,771) with a variable-data-rate-per-zone reference (US 4,750,059 / US 4,780,866) would target the claimed hybrid (coarse f-per-block plus fine n to hold f/(n·r) constant), which is the crux the '552 specification touts as its advance over pure CLV.

4. Explicit uncertainties

• I could not perform a native USPTO-database query; the citation set above is taken from the authoritative front page of US 5,063,552. If the USPTO Patent Center "References Cited" list differs from the Google Patents rendering, the USPTO list should control.
• My §102 conclusions rest on the claim language of '552 and on the summaries of the four references retrieved; I did not obtain the complete issued claim sets of US 4,530,018, US 4,514,771, US 4,750,059, or US 4,780,866 for a line-by-line element comparison, so the §102/§103 characterizations are reasoned assessments, not exhaustive claim charts.
• No reexamination, IPR, or ex parte reexam record on the '552 patent was surfaced in this pass; if any exists it could add or narrow prior art. I would not assert the absence of such a record without a direct USPTO proceeding lookup.

I'll ground the analysis in the actual prior-art references cited on the patent page. Let me pull details on each of the four references-of-record (plus the key "cited by" zoned-CLV art) so the combination analysis is accurate.

Let me get the operative details of US4530018 (Toshiba) — whether it varies the data rate per zone or only rotation speed — since that's pivotal to the combination analysis, and check how the courts treated the '552 validity challenge.

Obviousness Analysis — US 5,063,552 under 35 U.S.C. § 103

Builds on the previously generated claim overview (claims 1 & 9 independent; 2–8 and 10–16 dependent) and the litigation section (Ricoh v. Quanta). I do not repeat those; where relevant I cross-reference them.

Threshold caveat up front. This analysis relies on the four references the examiner actually cited ("Patent Citations (4)") plus their published texts as surfaced in search. I retrieved abstracts, claim language, and substantial description excerpts for these references, but not complete full-text PDFs, and I could not retrieve the W.D. Wis. opinions' specific § 103 reasoning as to the '552 patent. Where I am inferring rather than quoting, I say so. Patent numbers and dates are reproduced literally from the source page.

1. Governing law and the person of ordinary skill

• Statute: Pre‑AIA § 103(a) governs (application filed 1989‑07‑05; priority JP 63‑168135, 1988‑07‑06).
• Framework: Graham v. John Deere (scope/content of prior art; differences; PHOSITA level; secondary considerations), as refined by KSR Int'l v. Teleflex (2007) — motivation may be found in "any need or problem known in the field," and a predictable combination of known elements, each performing its known function, is obvious. Note the '552 was examined and issued (1991) long before KSR; a modern § 103 challenge would be evaluated under the more combination-friendly KSR standard.
• PHOSITA (my construction): A designer of optical-disk drive servo and data-format systems as of mid‑1988, familiar with (i) CAV vs. CLV formats and the density relation b = f/(2π·n·r), (ii) spindle motor control using encoders/PLLs and reference-clock division, and (iii) zoned recording formats and the access-time/speed-switching trade-offs. This is a well-defined, active art with a large body of pre‑1988 work.

2. The prior art of record (all pre‑date the 1988‑07‑06 priority)

Date nuance worth flagging: US 4,780,866 issued 1988‑10‑25 — after the '552's 1988‑07‑06 priority date — so it is available only as pre‑AIA § 102(e) art keyed to its 1986‑08‑25 filing date (which does precede the '552 priority). US 4,750,059 (issued 1988‑06‑07) falls within one year of the '552 filing, so it is § 102(a)/102(e) art rather than § 102(b). Both qualify, but the theory of availability differs.

3. Element‑by‑element mapping

Claim 1 / claim 9 element: (a) divide tracks into concentric annular blocks of different radii; (b) change f so it is constant within a block but different between blocks, depending on block radii; (c) change n so that f/(n·r) is constant.

Reading: No single reference has all three elements. But the ingredients are split exactly along predictable lines: '771/'018 supply (a)+(c) (zones + per‑zone spindle speed holding linear velocity roughly constant); '059/'866 supply (a)+(b) and expressly name the alternative modes. The '552's own specification concedes that both the CAV‑with‑rate‑change approach and the CLV approach were known, and that equation (1) b = f/(2π·n·r) was conventional. The claim's requirement (c) — "f/(n·r) is constant" — is nothing more than equation (1) with the constant 2π·b factored out.

4. The combinations

Combination A — '018 (primary) + '866 and/or '059 (secondary)

What it yields. '018 gives an optical disk divided into adjacent track groups whose angular speed is (i) held constant within a group and (ii) changed between groups so the average linear speed stays equal. '059/'866 give the complementary teaching: a zoned optical disk where each track in a zone carries the same number of bits, with the drive either stepping spindle speed per zone to hold the data rate uniform, or holding spindle speed constant and stepping the per‑zone data rate. Selecting the second mode ('059/'866) for the format and the fine spindle trim ('018) yields a system in which (a) gross density is equalized by choosing zone radii and per‑zone data rates, and (b) residual density error is removed by trimming n so that f/(n·r) is constant. That is claim 1 element‑for‑element.

Motivation (KSR).

1. Same field, same problem. All three references target the same objective: raise recording density above CAV without incurring the CLV penalty of a continuously swept spindle speed (access time, motor torque, power). '018's stated object is "high density… and high‑speed retrieval." '059/'866's stated object is efficient storage "without unduly complicating a drive mechanism," and they quantify the CLV penalty ("a few hundred watts… to change spindle speed within… one second or less").
2. Express identification of the design options. '059 and '866 do not merely hint at the two knobs; they state them as alternatives in a single passage ("uniform data rate" with speed steps vs. "maintain the angular velocity… constant and let the read data rate vary"). This is the classic KSR situation of a "finite number of identified, predictable solutions," which the Court held is obvious to try.
3. Predictable result, no criticality. The quantity being controlled (information density) obeys a closed‑form relation admitted in the specification (equation (1)). Any pairing of f and n that holds f/(n·r) constant yields identically uniform density. No unexpected result or new property arises.
4. Reasonable expectation of success / design incentive. '018 already teaches approximating constancy of linear speed group‑by‑group; refining that approximation with a within‑group spindle trim is the natural next step and requires only the encoder/reference‑divider motor loop that '018 and '866 both already disclose.

Combination B — '771 (primary) + '059 (secondary)

'771 is the closest single reference on the control side: it splits the disk into concentric zones, establishes an optimum spindle speed per zone to hold the head‑to‑media relative velocity constant, and does so with a DAC coarse command and tachometer fine loop. Its express rationale — change speed "only when this will result in enough additional capacity for an extra sector" — is a zoned‑capacity argument, i.e., it is already optimizing the interplay of spindle speed, sector count, and capacity. Adding '059's teaching to vary the data rate per zone (its "constant angular velocity / variable data rate" mode) supplies the missing element (b). Because '771's zone boundaries are drawn where an extra sector fits, the per‑zone data rate is naturally set by zone radius — satisfying claim 1's "different as between said blocks depending on the block radii."

Motivation. Both are zoned‑disk capacity schemes; '059 explicitly discusses zoned disks generally and the two data‑rate/spindle‑speed alternatives, and cites the equal‑width‑zone approach '771 embodies as prior art. A PHOSITA seeking to further improve zoned capacity, or to reduce the number of distinct spindle speeds a drive must support, would look to '059 and would be led with reasonable expectation of success to trade some spindle‑speed steps for data‑rate steps (or vice versa). Caveat: '771 is a magnetic‑disk reference; a challenger must establish that a PHOSITA in optical drives would consult it. The examiner's own citation of '771 against this optical‑disk application is evidence that the art considered it pertinent.

A single‑reference theory (weaker, but worth stating)

'059/'866 standing alone disclose a zoned disk drive in which the spindle is stepped to a discrete speed per zone and, alternatively, the per‑zone data rate is varied; a PHOSITA reading those documents would understand that both knobs act on the same underlying density equation. Combined with the admitted‑prior‑art CLV relation b = f/(2π·n·r), the claim's "f/(n·r) constant" limitation follows by algebraic necessity rather than invention. This is a weaker theory than A or B because neither Kodak reference shows the within‑block continuous n variation that the claim's (c) requires, but it is the theory most directly supported by the references' own text.

5. Dependent claims — incremental obviousness

If independent claims 1/9 fall, the dependents add little:

In short, the dependent claims are a textbook set of "obvious to try"/routine‑design limitations once the independent claims are met.

6. The strongest arguments against obviousness (what a challenger must overcome)

A rigorous analysis must state where the art genuinely falls short, because this is where a patentee would resist:

1. The coarse/fine split is not literally disclosed. The '552's actual insight is a division of labor between two control variables of different resolution and cost: f (hard to change finely) is stepped coarsely per zone, while n (easy to change finely) is trimmed continuously within a zone to keep f/(n·r) exactly constant. All four references keep n constant within a zone (a "zone speed") and adjust only at zone boundaries — '771 and '018 both describe a fixed speed for the duration of a zone. So the references teach zone‑wise discrete speeds, not the continuous within‑zone n = f/(2π·b·r) profile the claim requires. A patentee would argue this is a difference in kind, not degree, and would point to the specification's explanation that a high‑resolution change of f is impractical while a high‑resolution change of n is straightforward.
2. Potential teaching away. '059's criticism of the uniform‑data‑rate mode ("hundreds of watts… to change spindle speed within… one second or less") and its express preference for the constant‑angular‑velocity mode can be argued as a direction away from schemes that manipulate the spindle at all. '771's "maintained at that zone speed for motion within the zone" is similarly a step toward holding n fixed, not trimming it. This is a colorable—though, I think, ultimately beatable—teaching‑away argument: '018's "average linear speed … substantially made equal" language and '866's per‑zone speed‑control‑bit divider both contemplate active spindle manipulation, so the field was not uniformly away from it.
3. Presumption of validity and the examiner's allowance. The examiner had all four of these references of record and still allowed the application over them (the '018 and Kodak patents were the examiner's own citations). Under 35 U.S.C. § 282 the claims carry a presumption of validity overcome only by clear and convincing evidence. A challenger relying on the same references of record — without new art — starts behind.
4. Litigation track record (cross‑reference to the previously generated litigation section). In Ricoh Co. v. Quanta Computer, Inc., No. 3:06‑cv‑00462‑bbc (W.D. Wis.), the court did not dispose of the '552 on summary judgment (unlike the '109, which was held obvious, and the '955, held not infringed); the '552 went to trial, and the jury returned a plaintiff's verdict, with judgment of $14.5 million against Quanta Storage, Inc. (Nov. 24, 2009) after the Federal Circuit's 2009 remand (550 F.3d 1325). I could not retrieve the specific § 103 reasoning the district court or jury applied to the '552, so I cannot say whether the '018+'059/'866 combination was presented or rejected. But the practical inference is that a jury found the asserted claims valid and infringed at least once, which is real (if non‑dispositive) evidence of non‑obviousness.
5. Secondary considerations available to the patentee. The specification frames a concrete real‑world problem — CLV drives require large‑torque, power‑hungry motors — and claims a solution that preserves CLV‑equivalent capacity and format interchangeability with CLV discs while shrinking the motor. If Ricoh can adduce nexus‑bearing evidence (industry adoption of zone‑based CLV formats, licensing of the '552, the ongoing Ricoh family filings such as US 6,987,717 B2), those factors weigh against obviousness.

My assessment: points 1 and 3 are the real friction; points 2 and 4 are helpful to the patentee but not decisive. On the merits of the art alone, claims 1 and 9 look vulnerable under KSR‑era § 103 via Combination A; claims 2–8 and 10–16 add essentially nothing. The 1991 examiner's allowance over these references is best explained by pre‑KSR motivation standards and by the patentee's focus on the coarse/fine division of labor.

7. Corroborating art that is not prior art (flagged explicitly)

Several references surfaced that describe zone‑based hybrids but post‑date the '552 priority (1988‑07‑06) and therefore cannot be § 102/103 art for the '552 claims:

• US 5,182,741 (Sharp; priority 1989‑08‑25) — "Optical disk recording/reproducing device utilizing a constant angular velocity method with a constant linear velocity formatted optical disk."
• US 5,463,604 (Pioneer; 1992) — optical disc with data recorded at different rates on different zones, plus recording/reproducing apparatus.
• US 5,528,574 (Hitachi; 1992) and US 5,729,513 / 5,768,233 / 5,956,308 (Matsushita; 1992) — disk apparatuses with per‑zone/differentiated angular velocities.
• US 5,959,954 — "Information recording/reproducing apparatus with variable rate of revolution and data clock frequency," whose tables show per‑zone rates of revolution and per‑zone clock frequencies (a mature ZCLV implementation).

These are useful only as objective evidence of the field's trajectory — i.e., that after 1988 the industry converged on zone‑based combinations of data‑rate and spindle‑speed control, which is consistent with the '552's approach being the natural engineering next step rather than a departure. They must not be cited as § 102/103 prior art against the '552, and any analysis that does so is date‑defective.

8. Bottom line

• Claims 1 and 9 are exposed to a § 103 challenge built on US 4,530,018 (or US 4,514,771) as primary + US 4,750,059 and/or US 4,780,866 as secondary. The references collectively disclose every element: zone division of the disk, per‑zone variation of one of {f, n} to equalize linear density, and the motor‑control architecture (encoder + divided reference clock + per‑zone speed selection) needed to implement it. The motivation is supplied by the references themselves, which (a) attack the same density/access/power problem and (b) expressly enumerate the "change spindle speed" vs. "change data rate" options — a KSR "finite number of identified, predictable solutions" scenario with a predictable, algebraically determined result.
• Claims 2–8 and 10–16 would fall with the independents; claim 6/14 (n = f/(2π·b·r)) is the most exposed, being the specification's own admitted equation (1) rearranged, and claim 2/10's equal widths is described as prior art in '059.
• The genuine non‑obviousness case rests on the narrow but real gap that none of the references discloses the within‑zone continuous trimming of n combined with per‑zone stepped f — the coarse/fine division of labor — and on the § 282 presumption plus the litigation outcome noted in the previously generated litigation section ($14.5M verdict for Ricoh after the Fed. Cir. 2009 remand).
• Confidence: Moderate on the reference characterizations (based on published abstracts/description excerpts, not complete full texts); high on the dates, claim text, and the "cited by / post‑dating" classification; low on any assertion about how the W.D. Wis. court or jury actually analyzed § 103 for this patent, which I could not retrieve and therefore do not assert.