US 4513390

I'll run targeted searches for this patent number and check litigation dockets.

US 4,513,390 — "System for digital transmission and synthesis of integrated data"

Identification (as recorded in the authoritative Google Patents full text)

Continuity note (per the specification itself): "This is a continuation of application Ser. No. 037,228, filed June 8, 1979, abandoned." That is the source of the 1979‑06‑08 priority date — the 1981‑11‑16 date is the filing date of the continuation that actually issued.

Verified findings

1. The patent itself (high confidence — authoritative text supplied):

• Title, inventors, assignees, application number, dates, status and classification above are all confirmed directly from the Google Patents record at https://patents.google.com/patent/US4513390/en.
• The abstract is confirmed verbatim there: "An image acquisition subsystem, electronic processing subsystem and workstation subsystem produce information management networks that are almost unlimited in size and scope in integrating data and information stored in both digital form and in human readable form. Integration is by on-demand conversion in a scanner/digitizer of data and information to a transmittable, compatible electric signal which is encoded and converted into human readable form at the workstation of an information requester. The scanner rejects improperly oriented microfiche and recognizes microfilm data in a right reading or reversing orientation. An electronic circuit presents the data to the system's buffer in the right reading orientation regardless of a right or reverse reading input from microfiche. The scanner/digitizer regulates scanning speed in conformity with the data rate and capability of the transmission line to absorb the data. A microprocessor master module performs various functions with only minor hardware changes."
• The disclosure describes three subsystems (IAS / EPS / DWS) built from substantially identical, Z80-based microprocessor modules on a common system bus, with modules classed as "image sources" and "image sinks," DMA-based transfers, redundancy reduction (run-length coding), MTF/adaptive-threshold digitization from a 1,728-element CCD, and a switched direction so the line buffer can be emptied first-in-first-out or first-in-last-out to convert reverse-reading microfiche to right-reading.

2. Independent claims — plain language (moderate confidence: the claims section was not in the supplied full text; text below retrieved from a secondary database, https://insight.rpxcorp.com/patent/US4513390A):

• Claim 1 — An information system for storage, retrieval and generation of information from multiple multimedia sources, having three parts: an image-acquisition system, an electronic processing system, and a display workstation with output modules. The electronic processing system must contain, on a local system bus: (a) a serial input port module that receives data from the image-acquisition system and puts it on the bus; (b) a program module that directs the sequence and flow of information between the acquisition system and the workstation; (c) the workstation output modules on that bus; (d) a functional control module that controls the priority of operation of those output modules and thereby handles bus contention; (e) a redundancy reduction module that controls the digital data transfer rate through the bus; and (f) multiple output port modules for accessing further output modules, including memory and communication modules. Plain language: the glue-and-traffic-cop architecture claim — a multimedia capture/processing/display system where a program module orchestrates data flow, a control module arbitrates bus priority/contention, and a compression module throttles the data rate.

• Claim 6 — An information system for storage, retrieval and generation of information from multiple multimedia sources, comprising image-acquisition means, electronic processing means, and a display workstation with two display screens — one for high-resolution graphics, one for alphanumeric characters. The electronic processing system processes images acquired by the acquisition system; the workstation displays graphics derived from the processed images. The workstation further comprises a local bus, a processor module coupled to it, multiple output ports (high- and low-speed), an alphanumeric keyboard coupled to the bus, and local memory coupled to the bus, with the keyboard and memory cooperating with the processor module to control access to the ports. Each system element includes at least one microprocessor module, memory, direct memory access, I/O ports and bus interrupt control; the local bus has data, address, control and interrupt lines; and the electronic processing means is made up of a plurality of individual modules interfacing with the acquisition means and the workstation, each having means for locally controlling the system, the modules being substantially identical. Plain language: the dual-screen (graphics + alphanumeric) workstation claim plus the "interchangeable microprocessor module" architecture claim — the claimed novelty is the split high-resolution-graphics/alphanumeric display and the homogeneous, repeatedly-reused processor module on a bus with DMA and interrupts.

Uncertain applicable: I did not retrieve the text of dependent claims 2–5 and 7–15, so I cannot confirm how many independent claims exist beyond claims 1 and 6 (an independent claim at or near claim 11 or claim 15 is plausible but unverified). Treat the "independent claim" framing above as limited to claims 1 and 6.

3. Litigation / CAFC 2026 dockets:

• No CAFC appeal, PTAB proceeding, or 2026 docket involving US 4,513,390 was found. Searches for the number in Federal Circuit opinion/order materials and litigation-docket sources returned nothing referring to this patent. This is consistent with its expiration on 2002‑04‑23 (the patent was already expired roughly 24 years before the current date), which would preclude infringement litigation.
• Important number-confusion warning: searches for "4513390"-adjacent strings surface cases about different patents whose numbers merely resemble it — specifically U.S. Patent No. 8,451,339 (Netlist v. Samsung, Fed. Cir. Nos. 24‑1707 et al., opinion 2026‑09‑02; and Redstone Logics IPRs such as IPR2025‑00085 against MediaTek). Those relate to DDR memory modules/digital imaging and are not US 4,513,390. I did not merge those results into this summary, and you should not either.

Explicit uncertainties / data-quality flags

1. Claim text provenance. The authoritative Google Patents page as supplied ends mid-specification at the sentence "…first it must be assured that" and contains no claims section. The claim language quoted above comes from a third-party database (RPX/insight) and should be verified against the USPTO Patent Public Search / PatentCenter official copy before being relied on for any legal purpose.
2. Source internal inconsistencies (preserved, not corrected). In the supplied text, element number 10 is used both for the "document scanner and digitizer" and for the "general data processing device," and the phrase "Element 16" appears twice as a fragment. Additionally, the same description of the Z80A-DMA circuit and of "input command register / output status register" is duplicated. These appear to be OCR/transcription artifacts of the source document rather than substantive claim issues, but they mean the reference-numeral mapping in this record is not fully reliable.
3. Assignee chain. The record shows an original assignee of "Planning Res Corp" and a 1992 merger assignment to "PRC Inc., a corporation of DE." I have not independently verified any later ownership or the current owner of record beyond that listing.
4. Search scope. My litigation check was performed via general web search rather than a direct query of the CAFC docket system (PACER/CM‑ECF) or the PTAB API. A negative finding from this method is reasonably strong given the patent's 2002 expiration, but it is not the same as a certified docket-clear check.

Sources cited

• https://patents.google.com/patent/US4513390/en (authoritative full text, bibliographic data, abstract)
• https://insight.rpxcorp.com/patent/US4513390A (filing/issue dates, status, 15-claim count, claim 1 and claim 6 text)
• https://uspto.report/patent/grant/4513390 (bibliographic corroboration)
• Fed. Cir. opinion 24‑1707, 2026‑09‑02, and IPR2025‑00085 petition materials — cited only to identify the separate U.S. 8,451,339 patent as a distinct, non-relevant record.

I'll search for litigation involving US patent 4513390.

The initial searches returned results for different patents (e.g., Netlist's '339 and Optimum Imaging's 8,451,339), which I must not conflate with US 4,513,390. Let me search more precisely.

Still nothing specific. Let me try patent-specific litigation databases.

Direct answer

Based on the searches I was able to run (and the tool limit I hit), I found no evidence of any litigation involving US Patent 4,513,390 ("System for digital transmission and synthesis of integrated data," Gerard O. Walter & William D. Sheppard, originally assigned to Planning Research Corp., now PRC Inc.). I could not identify a plaintiff, defendant, jurisdiction, case number, filing date, or outcome for any case asserting this patent.

I want to be explicit rather than pad this with fabricated case data: I do not have high-confidence knowledge of any such case, and my searches did not surface one. I am not going to invent a docket.

What I searched and what came back

I searched for the patent number, its title, and its assignee against litigation-oriented queries. None of the hits concerned US 4,513,390. The results were all different patents or different rights with superficially similar numbers, which I am flagging so they are not mistaken for the target:

I did not obtain a usable result from the Unified Patents litigation portal (portal.unifiedpatents.com/litigation/caselist) before hitting the tool-call limit, so that source is unverified for this number.

Important context that bears on the answer

• Legal status: Google Patents records US 4,513,390 as "Expired – Lifetime," with an anticipated expiration date of 2002-04-23 (and an assignment to PRC Inc. of Delaware recorded 1992-01-21). A patent that expired in 2002 could still have been litigated during its ~17-year term (1985–2002), so expiration alone does not prove no litigation ever occurred — it only means no current infringement suit can be pending on this patent.
• Priority/filing: Priority date 1979-06-08; filed 1981-11-16 as a continuation of Ser. No. 037,228 (abandoned); granted 1985-04-23.

Honest limitations and recommended next steps

Because I could not complete a full sweep of the specialized litigation databases, treat "no litigation found" as my search result, not a certified negative. To confirm, the following sources should be checked directly for the exact string 4,513,390 (and it should be run against the patent's own parties — PRC Inc., Planning Research Corporation, and inventors Walter/Sheppard — since old cases may be captioned under assignee names):

1. Unified Patents litigation caselist — https://portal.unifiedpatents.com/litigation/caselist (filter by patent number).
2. PACER / CourtListener RECAP — docket-text search for "4,513,390" (CourtListener's RECAP archive is free and indexes many complaints).
3. USPTO Patent Assignment / PTAB — confirm no post-grant proceedings (a 1985 patent can't have IPRs, but assignment records may reference enforcement).
4. Westlaw/LexisNexis Docket or Darts-IP (if you have access) — these are the authoritative sources for older, pre-2000 litigation that is poorly indexed on the open web.

If you can point me at one of those portals or run one more targeted query, I can pin down any docket specifics rather than leave this at "not found."

I'll start by verifying the structured data against live sources.

The search results are pulling in US 8,451,339 — a completely different patent. Let me run more targeted queries to separate the two.

Search engines are conflating two different patents. Let me confirm by targeting the correct patent's identifiers and checking litigation databases directly.

⚠️ Read this first — a false-positive trap on the patent number

Before anything else: my web searches for this patent returned a large volume of PTAB material, but every hit was for U.S. Patent No. 8,451,339 (Optimum Imaging Technologies LLC), not U.S. Patent No. 4,513,390. The two numbers are digit-transpositions of each other (8,451,339 vs 4,513,390) and search engines collapse them. The material below is real, but it belongs to a different, much younger patent:

• Canon Inc. v. Optimum Imaging Technologies, LLC, IPR2020-01322 — institution denied on Fintiv discretionary grounds; Decision Denying Institution dated 2021-03-01 (Paper 9), followed by a Petitioner's Request for Rehearing (Paper 10). Petitioners' counsel: Venable LLP; Patent Owner's counsel: RuyakCherian LLP.
• Sony Corp. v. Optimum Imaging Technologies, LLC, IPR2024-00925 — described as pending in a later-filed petition.
• E.D. Tex. 2:19-cv-246, Optimum Imaging Technologies LLC v. Canon Inc., filed 2019-07-08, asserting the '805 and '339 patents; all claims dismissed with prejudice on 2021-04-29.
• A later third petition (unnamed in the excerpts I retrieved) urged General Plastic institution over Matsutani/Shiomi/Ito/Niikawa.

None of that touches U.S. 4,513,390, and I am not reporting it as a proceeding on this patent. I flag it because a defendant's counsel running a naive patent-number search will land on the Canon/Sony IPRs and could wrongly conclude the '390 patent has been litigated at the PTAB.

Proceedings overview

There are zero (0) AIA trial proceedings on file for U.S. Patent No. 4,513,390 — the USPTO Open Data Portal returns no IPR, PGR, or CBM for this patent, and no web source I could retrieve shows one; the breakdown is therefore 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution-denied, which means every claim of this patent is UNTESTED at the PTAB, but the reason is not that the patent is hardened — it is that the patent expired on 2002-04-23, roughly a decade before the PTAB's first AIA petition was ever filed.

No proceedings on file for US 4,513,390

• Type: N/A — no IPR, PGR, or CBM petition was ever filed.
• Filed: N/A.
• Status: No PTAB activity on file (per the structured "PTAB proceedings on file" block, sourced from the USPTO ODP API).
• Judge panel: None.
• Petition grounds: None. Note that PGR is categorically unavailable for this patent — PGR reaches only first-inventor-to-file patents (effective 2013-03-16), and U.S. 4,513,390 carries a 1979-06-08 priority date (application Ser. No. 037,228) / 1981-11-16 filing date. CBM review was also practically unavailable (it reached only financial-product/service data-processing patents, and the CBM window closed to new petitions on 2020-09-16). That leaves IPR as the only theoretically possible vehicle — and, as explained below, it is moot.
• Institution decision: None.
• Final Written Decision: None.
• Settlement / termination: None.
• Appeal: None. Although the patent was once assigned to PRC Inc. (a 1992-01-21 merger of Planning Research Corporation and Advanced Technology, Inc., recorded at the USPTO), and although Planning Research Corp. v. United States, 969 F.2d 1042 (Fed. Cir. 1992), is a real Federal Circuit case, that is a government-contract cost/accounting appeal, not a patent appeal on this patent — do not cite it as patent precedent.
• Defensive value: A defendant facing an assertion of U.S. 4,513,390 today should first attack standing/enforceability of an expired patent, not validity. The patent issued 1985-04-23 and reached its anticipated expiration on 2002-04-23 (17-year term from grant, the longer of the pre-URAA options). Any damages case is confined to conduct within the 35 U.S.C. § 286 six-year lookback from suit — which for a 2002 expiry means an infringement suit would have had to be filed no later than roughly 2008. There is no meaningful live assertion posture left.

Strategic summary

Claim status: 100% untested, 0% canceled, 0% sustained. Because no petition was ever filed, I cannot tell you that any claim of U.S. 4,513,390 has been invalidated — and I will not pretend otherwise. The patent as issued covers an image acquisition system / electronic processing system / display workstation architecture built on a standardized multi-module system bus with per-module microprocessors and DMA transfers (see, e.g., the FIG. 2b/2c module set and the claim-supporting disclosure at https://patents.google.com/patent/US4513390/en). None of that has been adjudicated at the PTAB.

Estoppel landscape: essentially empty. Because there are no petitioners, no § 315(e)(2) estoppel attaches to anyone. Any accused infringer would be free to raise any § 102/§ 103 ground — including art that a prior petitioner would have been barred from re-raising. Equally, no Patent Owner adverse-judgment or IPR-driven narrowing exists to concede. The flip side is that there is also no petitioner-funded invalidity work product sitting in the public record for you to reuse.

Pattern signals: none. No petitioner has filed multiple IPRs against this patent, the Patent Owner has never pursued a PTAB appeal on it (there is nothing to appeal), and no defensive aggregator such as Unified Patents appears anywhere in the chain. The "current assignee" on record is PRC Inc. following the 1992-01-21 merger; whether that entity or any successor still holds title is a chain-of-title question you should run before spending a dollar on the merits.

The structural reason there is no PTAB history. AIA trials began 2012-09-16. This patent expired 2002-04-23 — the events are non-overlapping. The only live window in which an IPR could even have been contemplated is the 2012–2017 stretch in which a hypothetical six-year lookback damages claim over pre-2002 conduct might have drawn a petition, and no such petition exists. Separately under current Office practice, a patent in force for this long would also draw a strong discretionary-denial argument on "settled expectations" (see the Acting Director's June–July 2025 discretionary-denial line of decisions, e.g., Dabico Airport Solutions Inc. v. AXA Power ApS, Paper 21, 2025-06-18) — but that doctrine is academic here.

Recommended next steps

1. Do not brief the merits yet. If you are a defendant and a demand letter cites U.S. 4,513,390, your opening move is a records check, not a prior-art search. Confirm the patent's legal status and expiration (Expired - Lifetime, anticipated expiration 2002-04-23, per https://patents.google.com/patent/US4513390/en) and whether any live exclusive right subsists.
2. Run the § 286 math. With an expiry of 2002-04-23, the six-year damages lookback means any actionable past-infringement theory reaches conduct before approximately 2008 at the very earliest — and the suit itself would have had to be timely filed relative to the expiry. Put the plaintiff to its proof on the damages window.
3. Verify chain of title. Assignment records show a 1992-01-21 merger transferring rights from Planning Research Corporation / Advanced Technology, Inc. to PRC Inc. (https://patents.google.com/patent/US4513390/en — Reassignment tab, and the USPTO Assignment database). Determine who, if anyone, holds enforceable rights today before treating an assertion as serious.
4. If — and only if — a genuinely live assertion emerges, an IPR is the sole AIA vehicle theoretically available (PGR is barred by the 1979 priority date; CBM's window closed 2020-09-16). But note two hard limits: § 315(b) gives you one year from service of a complaint to file, and the Board's current discretionary framework invites denial on settled expectations for a patent in force this long. In practice, invalidity in district court under § 282 is the cleaner path than an AIA petition.
5. Correct any internal memo that cites IPR2020-01322 or IPR2024-00925 as proceedings on this patent. Those are IPRs against U.S. 8,451,339 (Optimum Imaging Technologies) — a different patent with a different owner, and reporting them against 4,513,390 would be a factual error in any brief.

Bottom line: no PTAB activity exists on U.S. 4,513,390, and the absence is fully explained by the patent's 2002 expiration predating the AIA trial regime. This is not a "hardened" patent — it is an expired one, and that, not PTAB estoppel, is your defense.

I'll research the ownership chain for this patent, starting with the assignment records and the corporate history of the parties.

Good corporate-history signal. Now let me pin down the assignment records and the PRC→Litton→Northrop chain.

Let me try to surface the actual Assignment Center records, including reel/frame and correspondent.

I hit the tool-call limit before I could pull the Assignment Center record images, so this reconstruction is built from the authoritative Google Patents record supplied in this analysis plus verified press/regulatory sources on the corporate chain. Where a required field (reel/frame, correspondent) was not retrievable, I say so rather than guess.

Inventors

Pattern check: I found no evidence of all inventors departing the original assignee within 12 months of filing, and no evidence of inventor-side activity (no later inventor-owned assignments, no reversion, no inventor-named LLCs). Because I could not retrieve a complete assignment history, this is a negative finding on the evidence I have, not a certified negative. Note the file is a continuation of Ser. No. 037,228, filed 1979‑06‑08 (abandoned) — a ~2.4‑year pendency gap before the 1981‑11‑16 continuation was filed, which is ordinary and not a distress signal.

Original assignee

Planning Res Corp — i.e., Planning Research Corporation, McLean, Virginia (principal address in the relevant era: 1500 Planning Research Drive/Boulevard, McLean, VA 22102).

• Primary line of business: Professional services and systems integration / information technology for the U.S. federal government ("Beltway bandit"). PRC was founded in 1954 in Washington, D.C. by five scientists and engineers from the RAND Corporation, went public in 1964, and by FY1984 derived roughly half its revenue from computer services, principally federal systems work. (Sources: ASQ historical presentation at asq0511.org; archived industry profile at ia801201.us.archive.org.)
• Did they ship a product embodying the claims? Not determinable, and the specification points away from a hardware product. The disclosure describes PRC integrating a third‑party microfiche handler — "a conventional form of the foregoing microfiche handler is manufactured by Photometrics Corporation of Santa Monica, Calif." — and describes computer‑originated‑microfilm equipment as "conventional." That is consistent with PRC being a systems integrator that assembled a multimedia capture/processing/display system rather than a manufacturer of the claimed hardware. I found no commercial product literature tying a shipped PRC product to these claims.
• Current status: Acquired / no longer a standalone entity. Chain of control (verified): Emhart Corp. acquired PRC in 1986 ($220M); Emhart acquired Advanced Technology, Inc. (ATI) in 1987 ($140M); Black & Decker acquired Emhart in 1989; PRC and ATI were merged into PRC Inc. effective January 1, 1991 (Washington Post, "A Marriage Made in McLean," 1991‑01‑14); Black & Decker sold PRC Inc. to Litton Industries under a Stock Purchase Agreement dated 1995‑12‑13, closing February 1996 for $425M (FTC consent order, 1996‑02‑26; FTC press release 1996‑02‑16); Litton was acquired by Northrop Grumman (2001). There was no bankruptcy in this chain; Black & Decker solicited buyers repeatedly (1990 private auction, 1992 IPO withdrawn) but was solvent throughout.

Assignment timeline

⚠️ Data limitation stated up front: Google Patents' legal‑events table for US 4,513,390 shows one post‑issuance reassignment entry. I was not able to retrieve the reel/frame numbers, the executed (as opposed to recorded) dates, or the correspondent of record for any entry, because the tool budget was exhausted before I could query the Assignment Center record images. I am not filling those fields in with invented values. The reel/frame and correspondent fields below are marked NOT RETRIEVED.

1. c. 1979 – 1985 (exact execution date NOT RETRIEVED) — reel/frame NOT RETRIEVED

   • Conveyance: Assignment (inferred from the issued patent naming an assignee; document not retrieved)
   • Assignor: Gerard O. Walter; William D. Sheppard
   • Assignee: Planning Research Corporation
   • Correspondent: NOT RETRIEVED
   • Context: Ordinary inventor-to-employer assignment, enabling prosecution of Ser. No. 037,228 / continuation 06/321,540.

2. Recorded 1992‑01‑21 (execution date NOT RETRIEVED; note the underlying merger was effective 1991‑01‑01) — reel/frame NOT RETRIEVED

   • Conveyance: Merger (Google Patents legal events: "MERGER (SEE DOCUMENT FOR DETAILS)")
   • Assignors: Advanced Technology, Inc. and Planning Research Corporation
   • Assignee: PRC Inc., a corporation of Delaware
   • Correspondent: NOT RETRIEVED — cannot run the repeat-correspondent test without it.
   • Context: Internal corporate reorg / change of name by merger, not a sale. PRC and ATI — both then subsidiaries of Black & Decker — merged into PRC Inc. effective 1991‑01‑01; this 1992‑01‑21 recording is the papering of that merger. The presence of ATI as a co-assignor is the tell that this was a blanket portfolio recording covering both predecessor companies' patents, not a patent-specific deal.

3. 1996‑02 / 2001 — No patent-level assignment recorded in the retrieved record.

   • The Black & Decker → Litton sale (SPA dated 1995‑12‑13) and the Litton → Northrop Grumman acquisition (2001) are documented corporate transactions, but I found no reel/frame evidencing a patent assignment for US 4,513,390 arising from either. Absent that, the chain of title for this patent after 1992 is governed by the corporate-succession documents (merger/stock purchase), which typically do not generate per-patent assignment recordings.
   • Context: Successive acquisitions of the operating company. Nothing suggests a transfer to an asserter.

If the Assignment Center in fact holds only the 1992 merger entry and the original assignment, that is the complete record — and that is itself the finding (see verdict). Verification: USPTO Assignment Center — search the patent number 4513390 (also indexed at assignment.uspto.gov).

Contradiction to flag explicitly

My earlier summary recorded the current assignee as "PRC Inc." based on the Google Patents listing. That listing is stale: PRC Inc. ceased to exist as an independent entity when Litton acquired it in February 1996, and Litton itself was absorbed by Northrop Grumman in 2001. The USPTO assignee-of-record field and today's corporate reality therefore diverge. The "PRC Inc." entry is best read as the last recorded assignee, not the present-day owner of the asset. I have not verified a later recorded assignment to Litton or Northrop Grumman.

Timeline diagram

timeline
    title Ownership of US 4513390
    1979 : Parent application filed Jun 8
         : Inventors Walter and Sheppard
    1981 : Continuation filed Nov 16
    1985 : Patent issued Apr 23
         : Assignee Planning Research Corp
    1992 : Merger assignment recorded Jan 21
         : Assignors ATI and Planning Research
         : Assignee PRC Inc of Delaware
    1996 : Litton acquires PRC Inc
    2001 : Northrop Grumman acquires Litton
    2002 : Patent expires Apr 23

NPE / troll-pattern signals

Additional timing fact bearing on all of the above: the patent's anticipated expiration is 2002‑04‑23 and its status is "Expired – Lifetime." Any infringement suit would have had to be filed by that date, and no such suit surfaced. A 1985 patent also cannot be subject to IPR (AIA post-grant proceedings post-date it), so no PTAB proceedings are possible — that channel is structurally closed, not merely empty.

Verdict

Insufficient data. The retrieved evidence shows a coherent operating-company chain — Planning Research Corporation → PRC Inc. via a 1992‑01‑21 recorded merger, then Litton and Northrop Grumman by corporate succession — with zero affirmative NPE signals and no assertion activity, but the decisive fields needed to close the analysis were not retrievable: no reel/frame numbers, no correspondent of record, and no patent-level assignment recording for the 1996/2001 acquisitions. Because I have only the original assignment plus one intra-family merger entry, and because "no reels or only the original assignment" is the paradigm of the Insufficient data category, that is the honest call — not "Defensive/non-asserting" (the chain does not terminate at a defensive aggregator) and emphatically not an NPE category, since every entity in the chain was an operating federal-systems or defense contractor and the patent expired in 2002 with no identified suit.

Next steps to convert this to a firm verdict (all require the record images, not name inference): (1) pull reel/frame and correspondent of record for the 1985‑era assignment and the 1992‑01‑21 merger from assignmentcenter.uspto.gov using patent number 4513390; (2) search Assignment Center by the assignor names (Planning Research Corporation, Advanced Technology Inc., PRC Inc.) rather than the patent number, since blanket merger recordings are often indexed only by party; (3) check Black & Decker 10‑K (FY1996) and Litton 10‑K (FY1996) for IP-transfer schedules; (4) confirm in the RPX and Unified Patents asserter directories that no PRC/ATI patent has ever appeared in an NPE assertion campaign.

I'll search the USPTO and patent databases for US 4,513,390's citation records.

Let me try to retrieve the actual citation data from patent databases.

The citation lists aren't surfacing yet. Let me query the specific patent-record sites.

Bottom line first

I was not able to retrieve the actual "References Cited" / "Patent Citations" list for US 4,513,390, and I am not going to fabricate one. The authoritative full text you supplied ends mid‑specification (at "…first it must be assured that") and does not include the front‑page citation table. My searches against Google Patents, Justia/FPO‑style queries, and the CNU EDS patent record returned the forward citation trail (later patents that cite the '390), not the backward prior‑art list (references cited against it). I also exhausted my tool‑call budget before I could query the specialized sources that hold that table.

Below is (a) exactly what I verified, (b) why the distinction between forward and backward citations matters for your § 102 question, and (c) precisely where the backward list lives so it can be pulled and done properly.

What the searches actually returned

Confirming the important point: US 5,768,483 and US 2007/0201702 cannot "anticipate" US 4,513,390 under § 102, because both post‑date the '390's 1979‑06‑08 priority date. Being cited by a later patent says nothing about novelty. Only the backward references — those the Examiner placed in the "References Cited" table — are candidates for a § 102 analysis.

The legal frame the analysis has to sit inside (this is where the "which claims" question is decided)

US 4,513,390 issued from application 06/321,540, filed 1981‑11‑16, a continuation of Ser. No. 037,228 filed 1979‑06‑08. That makes it a pre‑AIA patent, so anticipation runs through pre‑AIA 35 U.S.C. §§ 102(a), (b), (e) and (g), not the AIA's § 102(a)(1)/(a)(2):

• § 102(a) — a reference must be by another and published/known before the invention date (presumptively the 1979‑06‑08 priority date, rebuttable by a Rule 131‑style swearing‑behind of the inventors).
• § 102(b) — a printed publication, patent, or public use more than one year before the U.S. filing date, i.e., before 1980‑11‑16. This is the trump card: § 102(b) art cannot be sworn behind.
• § 102(e) — an earlier‑filed U.S. patent/application by another, effective as of its filing date (this is why pre‑1981 U.S. filings matter even if they published after 1979).
• § 102(g) — prior invention by another in the U.S.; rarely relied on in an issued‑patent citation table.

So the practical screen for the citation table is: references dated before 1980‑11‑16 raise unswearable § 102(b) anticipation; references dated between then and 1979‑06‑08 are § 102(a)/(e) art only.

Claim‑level targets. Per the earlier section (claim text from RPX/insight — still flagged as needing USPTO verification), the anticipation‑relevant independent claims are:

• Claim 1 — the architecture claim (serial ingest port module; program module directing data flow; output modules on the bus; functional control module controlling priority of the output modules and thereby bus contention; redundancy‑reduction module controlling the digital data transfer rate; multiple output port modules including memory and communication). To anticipate claim 1, a single reference must disclose all of these on one system bus. In practice that is rare; expect § 103 combinations, not clean § 102.
• Claim 6 — the dual‑screen (high‑resolution graphics CRT + alphanumeric CRT) workstation plus the "substantially identical" microprocessor module architecture with DMA, I/O and bus‑interrupt control. Because "high resolution graphics" and "alphanumeric" screens were separately well known by 1979, claim 6's § 102 exposure turns on whether any single pre‑1979 reference shows them co‑located in one workstation on a shared local bus — and on the "substantially identical / interchangeable module" limitation, which is largely a structural‑equivalence question.

A reference that anticipates the scanner novelty (the microfiche‑orientation rejection sensors, right/reverse‑reading line‑buffer reversal, and transmission‑rate‑regulated scan speed) would attack the later dependent claims, not claims 1/6 — so the citation table needs to be read claim‑by‑claim, not as a flat list.

Why I could not close this out, and exactly where to get the list

My searches were general web searches, not a direct USPTO API or PatentCenter query, so treat "not retrieved" as my search failure, not as "no citations exist." The '390's front page will have a "References Cited" table (U.S. Patent Documents / Foreign Patent Documents / Other Publications). To pull it verbatim, these are the authoritative endpoints, in order of reliability:

1. USPTO Patent Public Search / PatentCenter — https://ppubs.uspto.gov/pubwebapp/ and https://patentcenter.uspto.gov/ — enter 4513390 exactly; the "References Cited" section is on the front page of the issued patent PDF.
2. Google Patents — https://patents.google.com/patent/US4513390/en — the "Patent Citations" and "Cited By" tables are on the page (the copy you supplied apparently truncated them). Note: Google's "Patent Citations" table mixes the backward list (references cited against the '390) with an "Cited By" table (forward) — do not conflate them.
3. Espacenet INPADOC / "Also published as" + citations — https://worldwide.espacenet.com/patent/search?q=US4513390 — gives the search‑report citations and family.
4. FreePatentsOnline — https://www.freepatentsonline.com/4513390.html — renders "Referenced Cited" and "Patent Citations" tables.
5. USPTO PTAB / assignment records — to confirm no post‑grant proceedings (none expected; a 1985 patent predates IPR).

If you can supply the front‑page citation table — or run one of those queries and paste the list — I will do the full § 102(a)/(b)/(e) mapping reference‑by‑reference, stating for each: full citation, publication/filing date, brief disclosure, and the specific claim(s) it could anticipate, with an explicit note of which citations fall on the pre‑1980‑11‑16 § 102(b) side.

Explicit flags

• No fabricated citations. I have deliberately returned an empty prior‑art list rather than invent reference numbers. Any list of "references cited in US 4,513,390" that I produced from memory would be a guess, and in a patent‑analysis context a wrong citation is worse than an absent one.
• Forward ≠ backward. The only citation‑family facts I verified (US 5,768,483; US 2007/0201702) are forward citations and cannot support anticipation of the '390.
• Claim‑text provenance unchanged. As noted in the prior section, the claim language comes from a third‑party database (RPX/insight); the § 102 claim mapping above is provisional until it is checked against the USPTO official copy.
• Date discrepancy (minor). Your task header says April 26, 2026; my operating environment date is 2026‑09‑28. It does not affect this analysis, but flagging it since you asked me to preserve inconsistencies rather than silently normalize them.
• Search-scope honesty. This was open‑web search, not a certified USPTO database pull. The negative ("list not retrieved") is a search‑limitation result, not an evidentiary finding.

Sources consulted: https://patents.google.com/patent/US4513390/en ; https://patents.google.com/patent/US20070201702 (cited‑by table listing US4513390A); https://library.cnu.ac.kr/eds/detail/edspgr_edspgr.05768483 (US 5,768,483 "Patent References Cited" listing 4513390); http://www.google.com/patents/sitemap/en/Sitemap/G06/G06F/G06F_3_3689.html (bibliographic corroboration).

I'll first try to retrieve the actual "References Cited" / prior-art section for this patent, since the supplied full text does not include it.

The searches confirm this patent is widely cited by later patents, but I still need its own front-page references. Let me try the Justia and Google Patents citation listings.

Let me try to surface the front-page "References Cited" for this patent directly.

Preliminary flag — the "Prior Art section" is not in the material I was given

Before the analysis, I have to be straight about an input problem, because it affects how you can use anything below.

• The authoritative full text supplied for US 4,513,390 contains no "References Cited" section and no claims. It ends mid-specification (at "…first it must be assured that"). The only thing resembling a prior-art field is the Google Patents "Prior art keywords" block: data, bus, image, module, scan, plus the classification entries G06F 3/00, 3/002, 3/005.
• I attempted to retrieve the patent's own front-page references (Google Patents citation table, Justia, patentimages PDF). Every search returned forward citations — later patents citing US 4,513,390 — not its own prior art. I hit the tool-call limit before obtaining the real list.
• Do not treat any of these as prior art to US 4,513,390 — they are all post-1985 and are therefore after the 1979-06-08 priority date: US 4,994,926; US 5,109,287; US 5,768,483; US 5,881,142; US 6,295,139; US 9,477,914; US 10,xxx (the Korean library hit listing "4513390 April 1985 Walter et al." was likewise a cited-by entry in US 5,768,483). If a prior-art section on your page lists these, that section is a forward-citation table, and using it as § 103 art would be an error.

So I cannot perform the task in its literal form ("use the results from the Prior Art section"). What I can do — and do below — is build the obviousness framework against (a) the admissions and named commercial components in the patent's own specification, and (b) the reference categories any competent § 103 ground would draw from, with confidence levels stated. Where I cannot name a verified reference, I say so rather than invent a number.

I am also building on the earlier sections: the claim text for claims 1 and 6 came from RPX/insight and is unverified; dependent claims 2–5 and 7–15 were never retrieved. That constrains this analysis to the two claims I can actually quote.

Obviousness analysis — US 4,513,390 under 35 U.S.C. § 103

1. Governing law and the correct § 103 provision

The application that issued was filed 1981-11-16 as a continuation of Ser. No. 037,228, filed 1979-06-08. Pre-AIA § 103(a) governs ("the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art"). AIA §§ 102/103 do not apply. The controlling framework is Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of art; differences; PHOSITA level; secondary considerations), as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (predictable combinations of known elements; "design incentives and other market forces"; "the improvement is [not] more than the predictable use of prior art elements according to their established functions"). MPEP § 2143 supplies the rationales.

Threshold caveat on practical effect: the patent expired 2002-04-23 and is recorded "Expired – Lifetime." There is no live infringement exposure, and no IPR is possible against an expired patent. A § 103 analysis of this patent today is therefore an archival/validity-reconstruction exercise (useful for defensive publication, licensing of an expired-technology portfolio, historical damages questions, or to test the strength of the earlier "no litigation found" conclusion). Nothing below changes the earlier litigation finding.

2. Level of ordinary skill in the art (PHOSITA), ca. 1979

A POSITA would have had: a B.S. in electrical engineering or computer science (or equivalent), plus 2–4 years of experience in digital document systems, and would have been familiar with — as the patent itself demonstrates by naming them — off-the-shelf 8-bit microprocessors (Zilog Z80A, with Z80A-DMA, Z80A-SIO/1, Z80A-CTC, Z80A-PIO), linear CCD image sensors (Fairchild CCD 121H with its "standard Fairchild" preamplifier board), parallel backplane buses with bus arbitration logic and DMA, contact/roll microfilm handling (the "conventional" Photometrics Corporation microfiche handler), commercial raster printers (RAPICOM, Versatec), and disk subsystems (XCOMP DCF-10 controller, CDC 9414 drive). This is a mature engineering art, not an emerging one; that is dispositive context for KSR purposes.

3. Claim construction of the two reconstructable independent claims

Claim 1 (per the unverified RPX text): an information system with image-acquisition system + electronic processing system + display workstation, where the processing system has, on a local bus: (a) serial input port module; (b) program module directing sequence/flow; (c) workstation output modules on the bus; (d) functional control module controlling priority of operation of the output modules and thereby handling bus contention; (e) redundancy reduction module controlling the digital data transfer rate through the bus; (f) multiple output port modules including memory and communication modules.

Claim 6: same three-subsystem architecture, with a dual-screen workstation (high-resolution graphics screen + alphanumeric screen), a workstation local bus with data/address/control/interrupt lines, processor module, high- and low-speed output ports, alphanumeric keyboard, local memory, and — the key structural limitation — each system element comprises a microprocessor module, memory, DMA, I/O ports and bus interrupt control, and the modules are "substantially identical."

Two construction points matter for § 103:

1. Claim 1's "functional control module … controlling priority of operation … and thereby handling bus contention" is not a novel circuit; it is the function of a bus arbiter, which the patent elsewhere attributes to the separate "bus controller board 52." Reading (d) and the spec's bus-controller description together, the limitation is met by any conventional priority arbiter.
2. Claim 6's "substantially identical" modules is a configuration/duplication limitation. Under KSR, mere duplication and reuse of a known module across nodes, where the results are predictable, is weak ground for non-obviousness absent an unexpected result. The patent asserts advantages (ease of expansion, no retrofitting except address tables) but those are exactly the predictable benefits of a standardized bus and homogeneous boards.

4. The "prior art" that is already inside this record (applicant admissions)

The specification is unusually rich in admissions under pre-AIA § 103 (and, where a printed publication or public use is implicated, § 102(b)). Verified verbatim from the authoritative text:

Consequence: Claim 1's elements (a), (b), (c), (e) and (f) are each individually admitted or shown to be conventional. The only live question under § 103 is whether the ordered combination — and specifically the split of traffic control between a "program module" and a "functional control module," plus a dedicated redundancy-reduction module sitting on the bus — was non-obvious. On this record, the individual elements are all admitted art, which shifts the burden to the patentee to show the combination produces an unexpected result. The record I have contains no evidence of unexpected results, no comparative data on the combination, and no secondary-considerations evidence at all.

5. Candidate § 103 grounds

Because I could not verify the actual cited references, I frame these as the grounds a competent challenger would plead, identified by reference type. Where the patent's own text gives me a verifiable anchor (named components, named standards), I use it.

Ground 1 — Facsimile/CCD document-scanning art + bus-interconnected multiprocessor data-processing art + run-length coding

• Primary reference (type): a 1970s linear-CCD facsimile scanner/transmitter that scans a document line-by-line, digitizes, buffers, compresses, and transmits over a switched telephone network. These are abundant by the 1979 priority date and squarely in the same field. (I cannot name a specific patent number with confidence, so I will not.)
• Secondary reference (type): a bus-organized, microcomputer-based data-processing system having a shared system bus, DMA controllers, and priority arbitration among requesting masters — the standard backplane architecture of the era (Intel Multibus, 1974; S-100, 1975; and Z80-family board systems). The patent's own Z80A/Bus structure is drawn from precisely this art.
• Tertiary reference (type): a run-length encoding/decoding standard or published description — the patent itself cites "the CCITT/3 standard."

Motivation to combine: the explicit, admitted bottleneck. The spec states a voice-grade line "can support, with present technologies, up to ninety six hundred digital pulses per second," while an uncompressed page is ~3.8 million picture elements = "seven minutes for transmission." That is a finite problem with a finite, articulable solution — conserve bandwidth — and run-length coding was the recognized answer. Coupling a compressor to the bus of a modular processor system so that all sources and sinks share it is the predictable use of known elements for their established functions (KSR). Reasonable expectation of success is high: both the compression technique and the bus architecture were proven independently.

Weakness in this ground: none of it addresses claim 6's dual-screen limitation.

Ground 2 — Micrographics retrieval/scan art + networked data-processing architecture

• Primary artifact (type): an automated microfiche storage-and-retrieval scanner with a platen, transport, and digitizer — the spec admits the Photometrics Corporation handler was a "conventional form" of exactly this.
• Secondary reference (type): a host-based, interactive data-retrieval network in which a central processor services multiple remote terminals and arbitrates access to shared peripherals (the patent admits "on-line interactive exchange between the operator and the digiral data bank system supervisor").

Motivation to combine: the admitted market need — the spec itself frames the objective as making "hard copy form, … digital machine readable form and … micrographic form … easily accessable" regardless of geography. That statement is an express problem statement, and under KSR a problem articulated in the specification can itself supply the motivation to combine known solutions. Replacing a human microfiche reader with an on-line digitizer and putting it on a shared bus with a disk store and a printer is the straightforward automation of a known manual workflow.

Ground 3 — Dual-display workstations (the strongest ground against claim 6)

Claim 6's distinguishing limitation is the side-by-side high-resolution graphics screen and alphanumeric screen. The specification supplies the motivation almost verbatim:

"high resolution graphics cannot be displayed efficiently on CRT's designed for alphanumeric display. In addition, alphanumeric display on high resolution graphics require special character patterns such as 15 × 21 dots rather than 5 × 7, and finally split screen displays often require large and high resolving CRT screens that are not available except on special order and at high expense."

That is a textbook KSR rationale: an identified design need plus a finite number of predictable solutions. Given that high-resolution raster display (1200-line) and character-generator alphanumeric display (24 × 80, 5 × 7 matrix) were each independently well known, and that a dual-monitor engineering/phototypesetting workstation was itself a known configuration, placing one of each in a single workstation connected through a common local bus with keyboard and local memory is a predictable combination with a reasonable expectation of success. The patent claims the cost-avoidance benefit ("not available except on special order and at high expense") — which is precisely a market-force motivation recognized in KSR.

The "substantially identical modules" limitation of claim 6 falls to the same combination plus the admitted modular bus art: homogeneous, interchangeable processor boards on a common backplane were the defining convention of S-100/Multibus/Eurocard practice. The patent's asserted benefit ("the addition or deletion of different image sources or sinks causes no retrofitting … except for the updating of the address table") is the definition of a standard bus, i.e., a predictable result, not an unexpected one.

Ground 4 — Peripheral-automation art against the read-orientation features (only if claims cover them)

If any dependent claim recites the right-reading/reverse-reading line-buffer reversal or the "reject a rotated fiche" sensor logic (the features emphasized in the abstract and at ~col. 8 of the spec), the strongest attack is automation of a known manual step: microfilm generation conventions (odd generations reverse-reading, even generations right-reading; NMA/ANSI corner-cut and cut-mark standards) were documented standards, and the spec admits both the standard and the generation behavior. Detecting a standard corner cut with two photosensors and reversing a shift register's output order (FIFO vs. FILO) are ordinary engineering choices. This is the ground I would expect to be most contested, because the patent ties a sensor-detected generation determination to a buffer read-direction control — a two-step logical linkage that a challenger must show was suggested by the standards themselves. I flag it as medium confidence given I lack the dependent claim text.

6. What is not obviously vulnerable (candidate non-obvious core)

On the record I have, the feature with the best non-obviousness story is not in claim 1 or claim 6 but in the specification/abstract: the closed-loop scan-rate servo. The spec states that instead of a multi-megabit MOS page buffer (which it calls the "conventional solution" and characterizes as expensive), it uses a small ~10-scan-line MOS buffer plus "electronic circuitry 162 … that senses the speed at which this 10 line buffer empties into the transmission line and feeds back a speed up or slow down command, through the motor control 152, digital to analog converter 154 and servo 156, to the scanning carriage 136." That is a teaching-away-flavored passage (the prior art buffer was not merely different, it was characterized as "a considerable expense") and could be argued as a specific, non-trivial control loop. However: (i) I do not know whether any claim recites it; (ii) "sense buffer fill level and feed back a speed command" is itself a classic control technique; and (iii) In re the teaching-away argument, the reference must criticize the claimed alternative, and here the "conventional solution" being criticized is a different structure, not the claimed one.

7. Deficiencies in this analysis you must resolve before relying on it

8. Bottom line

• On the elements I can verify — the specification's own admissions that facsimile transmission, run-length coding ("standard … per CCITT/3"), scratch-pad buffering, bus arbitration, DMA, the Photometrics fiche handler, the Fairchild CCD 121H, the XCOMP/CDC disk subsystem and RAPICOM/Versatec printers were conventional or commercial — claim 1 is highly vulnerable under pre-AIA § 103(a): it reads as the predictable assembly of admitted elements on a standard bus, and the patent asserts no unexpected result from the combination.
• Claim 6 is vulnerable on two independent routes: (i) the dual-screen limitation falls to the KSR rationale the specification itself articulates (high-res graphics "cannot be displayed efficiently on CRT's designed for alphanumeric display" + cost/availability of large high-res CRTs = articulated design need with a finite set of solutions), and (ii) "substantially identical microprocessor modules" is standard-bus conventionality with only predictable benefits.
• The most defensible subject matter is the closed-loop, buffer-fill-controlled variable scan rate — but I cannot confirm it is claimed, and it is legitimately arguable either way.
• I could not complete the task as literally specified (use the Prior Art section), because that section is absent from the supplied record and my searches returned only forward citations. Every combination above is therefore framed by reference type and anchored to verified text from the patent itself, not to retrieved reference numbers. Treat the grounds as pleadable skeletons requiring the real references of record — I have deliberately not fabricated any patent numbers.