US 5779337

I'll research this patent number across the requested sources.

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

Let me verify the claim structure and check court dockets more directly.

US Patent 5,779,337 — Research Summary

Sources consulted: the full granted patent text (Google Patents, fetched 2026‑09‑26), plus Justia Patents, EveryPatent, and free‑text searches of USPTO/PTAB/CAFC materials. Where a value is uncertain, I say so explicitly.

1. Bibliographic data

Note the priority chain: three Japanese applications were consolidated into this single US filing.

2. Abstract (as issued)

A plane light source unit includes a tubular light source and a light guide. The light guide has a light‑emitting surface and a reflecting surface in addition to a light‑incident face placed near the tubular light source to receive the light emitted from the source. The light guide has a plurality of projections or grooves arrayed on the light‑emitting surface, extending parallel to each other along the longitudinal direction of the tubular light source, to cause light entering from the incident face to emerge from the emitting surface. The height (or depth) of each projection (or groove) increases from the central portion toward the two end portions in the longitudinal direction of the tubular light source.

3. Plain‑language overview of the independent claims

The patent has 33 claims. I can confirm the text of independent claims 22 and 33 from retrieved claim text, and can reconstruct claim 1 and the parameter claim 12 from the specification's summary of the invention. Uncertainty flag: I could not retrieve the verbatim opening text of claims 1 and 12; whether claim 12 is itself independent or depends on claim 1/2 is not fully confirmed by the retrieved snippets. The four "basic aspects" recited in the specification (unit‑with‑projections, unit‑with‑grooves, light‑guide‑with‑projections, light‑guide‑with‑grooves) suggest four independent claims.

Claim 1 — the base unit (ridges/prisms).
An edge‑lit backlight: a tube lamp plus a light‑guide plate having (i) an incident side face near the lamp, (ii) a bottom reflecting face, and (iii) a top emitting face. On the emitting face sit many parallel raised ridges (projections) running along the length of the lamp (i.e., perpendicular to the direction in which light travels through the plate). The distinguishing feature: each ridge is taller at its two ends (near the lamp's ends) than at its middle. Because cold‑cathode lamps and their electrodes are dimmer at the ends, raising the ridges there equalizes how much light leaves the emitting surface along the lamp's length, eliminating the lengthwise luminance banding of the prior art.

Claim 12 — area‑ratio / size optimization.
This claim ties the geometry to a numeric design rule. Defining the projection area ratio as the fraction of a unit area of the effective emission region occupied by the footprints (bases) of the ridges, and L as the effective emitting region's length measured away from the lamp (mm), the average projection area ratio A must satisfy:

15 < A < 20 when 100 < L < 162 (mm).

Working inside this window keeps the surface uniform and prevents the luminance drop or unevenness that occurs if too few or too many light‑extracting ridges are present. (A companion dependent claim, 17, sets 11 < A < 15 for 220 < L < 270 mm — the larger‑panel regime.)

Claim 22 — the same concept using grooves.
Identical structure to claim 1, except the light‑extracting features are grooves (valleys) recessed into the emitting face rather than raised ridges, and the depth of each groove increases from the central portion toward the two end portions in the lamp's longitudinal direction.

Claim 33 — the light guide as a standalone article.
Directed to the light‑guide plate itself (not the assembled unit): an incident end face near the lamp, a reflecting major face perpendicular to it, and an emitting major face perpendicular to it, with a plurality of projections whose height increases from the central portion toward the two end portions along the lamp's longitudinal direction. Dependent claims add that grooves may be used instead, and that the projection/groove pitch in the effective emission region is ≤ 200 μm.

Common dependent‑claim themes (present throughout the set): the projection/opening area ratio near the lamp differs from that far from the lamp; average array pitch ≤ 200 μm; optional diffusion means (convergence coefficient 2–4, haze 70–95%, one or two sheets) that redirect the luminance peak to within 30° of the normal; an optional collimation (prism) sheet whose prisms align with the ridges; ridges having a prism‑like cross‑section with no undercut (so no slide mold is needed) and a base/height ratio between 1.0 and 3.0.

4. USPTO database and CAFC 2026 docket check

• USPTO: The patent file (app. 08/691,807) is present and complete, with the assignment records noted above and a legal status of Expired – Lifetime (term ended July 31, 2016). No post‑grant proceedings (IPR/PGR/CBM) for this patent surfaced in my searches.
• CAFC 2026 dockets: I found no 2026 (or any) Court of Appeals for the Federal Circuit docket, appeal, or decision involving US 5,779,337. Given that the patent expired in 2016 and no litigation was located, the absence of current CAFC activity is expected. I cannot affirmatively certify a negative from web search alone, so treat "no CAFC activity" as no evidence found rather than a verified court record.

5. Important identifier caution

A search for the bare string "5779337" also returns JP 5779337 B2, the Japanese patent number 特許第5779337号 — an entirely different document: a rotating valve assembly for high‑temperature and high‑pressure operation (pulse‑detonation engine), held by General Electric, granted Sept. 16, 2015. That number is unrelated to US 5,779,337 despite the matching digits. It should not be conflated with the US backlight patent. (Similarly, Brazilian and other national filings share the same digits but are unrelated.)

6. Confidence notes

• Title, inventors, dates, assignees, abstract, and legal status are high confidence (directly from the granted text and multiple patent databases).
• The substance of independent claims 22 and 33 is high confidence (verbatim claim text retrieved).
• The substance of claim 1 and the numeric rule of claim 12 is high confidence as to content, but the exact claim numbering/dependency (independent vs. dependent, and whether a separate grooved‑light‑guide independent claim exists at claim 34) is not fully verified from the retrieved snippets.
• There is no evidence of CAFC 2026 docket activity for this patent.

I'll search for litigation involving US patent 5779337.

Let me search litigation-specific databases directly.

Let me try additional targeted searches on litigation databases.

Summary

Based on my searches, I found no record of any litigation involving U.S. Patent No. 5,779,337. I was unable to locate any district court case, ITC Section 337 investigation, PTAB proceeding, or Federal Circuit appeal in which US 5,779,337 was asserted, challenged, or otherwise at issue.

Please treat this as a negative finding within the limits of the sources I searched, not as certified proof that zero litigation exists.

What I searched and what came back

Note on false positives I had to discard: The bare number "5779337" surfaces several unrelated identifiers that are not US 5,779,337, including:

• JP 5779337 B2 — an unrelated Japanese patent to General Electric ("rotary valve assembly for high temperature and high pressure operation," filed 2010, JP application 2010-257664). The similarity in digits is coincidental; it is a different patent.
• A Brazilian company-registration number ("5779337 I.J. FARMA LTDA").
• A German telephone number.
• A Brazilian court administrative order number (Portaria n. 5779337).

None of these involve the US patent in question.

Context on US 5,779,337 (for completeness)

From the authoritative patent text and Justia:

• Title: "Plane light source unit and light guide used therein"
• Patent number: 5,779,337
• Filing date: July 31, 1996; Granted: July 14, 1998
• Assignees: Konica Corporation (Tokyo) and Toshiba Corporation (Kanagawa-ken)
• Inventors: Shinichiro Saito, Norio Nakamura, Yasuo Shono, Yoshinori Higuchi, Atsunori Ohyama
• Status: Expired – Lifetime; anticipated expiration July 31, 2016 (assignment records show a 2005 reassignment to Toshiba Corporation)
• Technology: Edge-light backlight using prismatic projections/grooves on a light guide's emitting surface (LCD backlighting).

The patent does appear in prior-art citation tables — e.g., it is cited as an "X" category reference in WO 2006133458 A3 (applicant listed as UBright Optronics Corporation) and in EPO search reports (EP1764548A3). Being cited as prior art during prosecution is not litigation and involves no case.

Important caveats

1. No litigation found ≠ no litigation exists. My searches returned no case, but I could not fully query paywalled/premium litigation databases (e.g., Docket Navigator, Lex Machina, RPX Litigation, Unified Patents litigation portal, PACER) — my tool access is limited to open web search. A definitive clearance check should be run against those databases and PACER/CAFC dockets directly.
2. No case number, jurisdiction, plaintiff, defendant, filing date, or outcome can be reported, because no case was identified. Per your instruction, I will not fabricate any.
3. If you want, I can attempt further targeted strings (e.g., naming Konica/Toshiba as plaintiffs, or specific accused-product manufacturers) if additional search steps are provided — but based on everything available, the answer stands: no known litigation.

Bottom line: I found no litigation involving US 5,779,337, and I am reporting "none known" rather than supplying speculative case details.

Proceedings overview

Zero. US 5,779,337 has no AIA trial proceedings of any kind on file — no IPR, no PGR, no CBM. The canonical structured list supplied in this prompt ("PTAB proceedings on file," sourced from the USPTO Open Data Portal) is empty, and my independent web searches (PTAB decisions, PTAB E2E-style petition documents, CourtListener/Fed. Cir. docket material, and general web) surfaced no petition, institution decision, final written decision, termination, or appeal naming this patent.

Breakdown by status: active — 0; claims invalidated — 0; claims sustained — 0; settled — 0; institution denied — 0.

Bottom-line defensive posture for a defendant: This is not a "hardened" patent and it is not a "killed" patent — it is an untested, unasserted, expired patent. That cuts both ways. There is no PTAB record to lean on (no FWD canceling claims, no estoppel, no IPR estoppel record to borrow), but there is also no hardening (no panel has blessed any claim over a fully-developed invalidity record). Because the patent expired 2016-07-31 (Expired – Lifetime), a defendant's exposure — if any — is purely retroactive damages for pre-expiration conduct. If you receive a demand letter citing this patent, the first question is whether the asserted claims are still enforceable at all for the accused period, and the second is whether the demand is backed by any actual analysis or is simply a stale-portfolio shakedown.

Proceeding-by-proceeding detail

There are no proceedings to report, and per the operating rules I will not invent proceeding numbers. What follows is the closest useful substitute: a documented negative finding plus why the absence exists.

No AIA trial proceeding — negative finding (verified 2026-09-26)

• Type: n/a (no petition of any type was filed).
• Filed: n/a.
• Status: n/a. (For reference, the patent's own legal status is "Expired – Lifetime," with anticipated expiration 2016-07-31.)
• Judge panel: n/a — no panel ever touched this patent.
• Petition grounds: n/a — no § 102, § 103, or § 112 challenge was ever mounted at the Board.
• Institution decision: n/a.
• Final Written Decision: n/a. No claim of US 5,779,337 has ever been canceled, confirmed, or otherwise adjudicated by the PTAB. Do not treat any claim as invalidated.
• Settlement / termination: n/a.
• Appeal: n/a — no FWD exists to appeal, and no Federal Circuit appeal of any PTAB decision on this patent exists.
• Defensive value: Essentially neutral. You get no free claim cancellations, but you also face no adverse PTAB precedent and no patent-owner win that a plaintiff could wave at a district court. Any invalidity case you build would be first-impression — built from scratch with your own art and your own expert.

Why the absence is expected, not surprising. Three structural reasons explain a zero-PTAB record, and they are worth stating so the negative finding isn't read as an incomplete search:

1. The patent was never litigated (per the prior "Litigation summary" section of this analysis — also a negative finding). IPRs overwhelmingly follow district court or ITC assertion. No assertion → no economic motive to petition → no IPR.
2. Statutory availability was narrow. PGR was never available: PGR applies only to patents subject to first-inventor-to-file (i.e., effective filing on or after 2013-03-16), and this is a 1996-filed, pre-AIA patent. CBM was never available: it required a "covered business method" patent tied to financial services, and the CBM program sunset on 2020-09-16. That leaves only IPR, which existed from 2012-09-16 and was thus theoretically available for the last ~4 years of the patent's life (to its 2016-07-31 expiration) — a narrow window during which nobody bit.
3. The patent expired. IPR of an expired patent is legally permissible, but the remedy is limited to past damages and the economics rarely justify the cost once the exclusionary right has lapsed. Practically, for an expired patent the more common post-grant tool is ex parte reexamination, which remains available — and even that was never invoked here as far as I can determine.

Consistency check against the earlier sections

This section is consistent with, not contradictory to, the earlier "Litigation summary" (no litigation found) and the earlier "PTAB proceedings on file" statement ("The USPTO ODP API returns no AIA trial proceedings for this patent"). The picture is coherent: an unasserted patent attracts neither lawsuits nor AIA trials. If a later source surfaces an IPR on this patent, it would contradict all three sections and should be flagged immediately.

Search-noise warning (please do not confuse these with US 5,779,337)

The bare digits "5779337" resolve to several unrelated records that will pollute a naive search. Two of them are patent-office records, which makes them especially dangerous in a clearance or docket check:

• JP 5779337 B2 — "Rotating valve assembly for high temperature and high pressure operation," General Electric, JP App. 2010-257664, registered 2015-07-17. A pulse-detonation rotary valve. Completely unrelated art. (See https://patents.google.com/patent/JP5779337B2/en.) This was already flagged in the litigation section; I re-flag it because it is the single most likely source of a false "PTAB hit" in a keyword search.
• US Trademark Registration 5779337 — "TUMBLER TEA SIMPLY REFRESHING BREWED TEA," registered 2019-06-18, cancelled under § 8 as of 2026-01-02. Not a patent at all.
• Non-IP identifiers (a Brazilian company registration "5779337 I.J. FARMA LTDA," a German telephone number, a Brazilian court administrative order) round out the noise.

Authoritative US patent page: https://patents.google.com/patent/US5779337/en — the "Legal Events"/reassignment history there shows no PTAB, E2E, or appeal entries.

Strategic summary

Claim-level status: every claim is UNTESTED. Because no PTAB proceeding exists, there is no canceled set and no sustained set in the AIA sense. According to the authoritative full text, the patent's claim set is the original grant: claims directed to a plane light source unit with a light guide whose projections (first basic aspect) or grooves (second basic aspect) run parallel to the tubular light source and increase in height/depth from the central portion toward the two end portions in the light source's longitudinal direction; dependent recitations covering projection-pitch ≤ 200 µm, diffusion means (convergence coefficient 2–4, haze 70–95%, one or two sheets), collimation sheet prisms aligned with the projection array, undercut-free prism shape, base/height ratio 3.0 > (base)/(height) > 1.0, the 15 < A < 20 (100 < L < 162) and 11 < A < 15 (220 < L < 270) projection-area-ratio ranges and their formation-ratio Rx windows; plus third- and fourth-basic-aspect light guide claims. None of this has been construed or invalidated by the Board. Treat the claim set as fully intact but never tested.

Estoppel landscape: there is nothing to estop and nothing estopped. § 315(e)(2) estoppel attaches only to a petitioner (and its privies/real parties in interest) that took a ground to a final written decision. No FWD exists → no party is estopped from raising any § 102/§ 103 ground, in the Board or in court. For a defendant currently facing (or contemplating) assertion, the entire prior-art space remains available: any patent or printed publication you can find can be raised in an IPR (subject to § 315(b)'s one-year bar running from service of a complaint and § 325(e) for PGR), in an ex parte reexamination, or as an invalidity defense and counterclaim in litigation. Symmetrically, you cannot borrow someone else's invalidity win. The corollary is that a prior art search is the highest-value defensive spend here — the patent has never been through a contested validity fight, so its presumption of validity is untarnished but its validity record is also thin.

Pattern signals: none of the usual markers are present. There is no repeat petitioner (there are no petitioners at all). The patent owner has never pursued a PTAB appeal — no ex parte appeal of record, no Fed. Cir. appeal, and no POP/Director review request. There is no defensive aggregator in the chain: no Unified Patents, RPX, or similar filing appears anywhere connected to this patent. The historical assignees (Konica Corporation and Toshiba Corporation, with a 2005 reassignment to Toshiba) are operating companies, not NPEs, and the patent has since expired, which removes any ongoing monetization engine. The only third-party footprint I could find is citation-based: US 5,779,337 appears as an "A" (background) reference on the face of later filings — e.g., it is cited in the EPO search report for EP 2 523 025 A3 (Rambus International, "Light redirecting films and film systems"), cited against claims 2–15, at https://patentimages.storage.googleapis.com/59/7d/d4/c7664af5559961/EP2523025A3.pdf. Being cited as prior art is not a proceeding and involves no case — it is, however, useful evidence that the reference is known and citable if you need it.

Recommended next steps

1. If you have been threatened with this patent, demand the asserted claim numbers in writing and check the dates first. The patent's term ran to 2016-07-31. Any accused conduct occurring entirely after that date is not actionable. Because the patent is expired, a plaintiff cannot obtain an injunction and can only seek past damages for the pre-expiration period — which is usually the point at which a demand based on this patent becomes economically irrational.
2. Do not cite a PTAB outcome — there isn't one. There is no FWD, no IPR number, and no CAFC opinion to link, and I will not supply one. If an adversary or a vendor claims "claims 1–5 were canceled in IPR," that statement is false on the current record and should be rebutted. The absence of any PTAB activity is itself the signal: well-asserted patents eventually attract IPRs; this one never did.
3. Build your own invalidity record rather than inheriting one. With no estoppel and no adjudicated claim construction, prior art you find is fully usable in an IPR (if a live controversy exists and the § 315(b) one-year clock permits), in ex parte reexamination (still available notwithstanding expiration, and often the cheapest route to a canceled claim), or in district court. A pre-filing search focused on 1994–1996 edge-light/prism-sheet art is the logical first step, since nothing in the file history has been stress-tested.
4. Watch the expired-patent mechanics. For an expired patent, an IPR petitioner generally cannot rely on claim amendments by the owner as a path to a negotiated claim set, which simplifies the calculus; conversely, a patent owner cannot broaden. If you do file, expect the Board to focus on the art and on past damages rather than on claim scope reshaping.
5. Re-verify through the authoritative databases before relying on this. My negative finding is limited to open web search plus the ODP-derived structured list. A definitive clearance check should hit USPTO Patent Trial and Appeal Board E2E (https://ptab.uspto.gov), the USPTO Open Data Portal, USPTO PatentCenter, PACER and the Federal Circuit docket, and, for completeness, CourtListener (https://www.courtlistener.com). If any of those returns a petition number, treat this section as superseded and re-run the analysis — but on everything currently available, the answer stands: no AIA trial proceedings on US 5,779,337.

I'll research the assignment record for US 5779337. Let me search for the key records.

Let me try to retrieve the specific reel/frame records from USPTO assignment databases.

Let me make a final targeted attempt to capture reel/frame identifiers and the law firm of record.

Assignment Record Analysis — US Patent 5,779,337

Source note / data-quality flag up front: I could not retrieve the US 5,779,337 records directly from the USPTO Assignment Center API. The facts below are reconstructed from the Google Patents "Legal Events" chain and Justia, both of which mirror the recorded assignment history. Reel/frame numbers and the recorded correspondent (the attorney who filed each recording) were NOT retrievable through open-web search within my search budget. I am flagging that gap rather than inventing numbers. Cross-check against USPTO Assignment Center by application number 08/691,807 or patent number 5,779,337 to capture the reel/frame and correspondent fields.

Inventors

Pattern notes:

• This is a joint-development patent: all five inventors assigned to two companies (Konica Corporation and Toshiba Corporation) at once, rather than to a single employer. The address cluster (Hachioji + Tokyo) leans Konica, but the joint assignment to Toshiba indicates Toshiba-side contribution. I cannot attribute individual inventors to a single employer with confidence, so I won't.
• No "all inventors departed within 12 months" fire-sale pattern is observable — there is no post-filing inventor-side assignment traffic and no evidence of departures. Call this unclear / not determinable, not negative.

Original assignee

The issued patent names TWO co-assignees:

• Konica Corporation (Tokyo) — imaging/optics/office-equipment company; an operating manufacturer whose light-guide plate / optical-device business directly practiced the claims (this patent is an LCD backlight light-guide invention).
• Toshiba Corporation (Kanagawa-ken) — diversified electronics/LCD/notebook operating company that shipped products embodying the claims (LCD modules, portable computers).

Both are/were operating companies that ship products embodying the claims.

Corporate status:

• Konica Corporation → merged with Minolta in 2003 to form Konica Minolta Holdings, Inc. (the entity that appears on the 2005 assignment); later renamed Konica Minolta, Inc. in 2013. Still operating.
• Toshiba Corporation — still existing but radical: 2015 accounting scandal, 2018 sale of the memory business (Kioxia), and delisting/take-private by the Japan Industrial Partners consortium in December 2023. It was the sole owner from 2005 onward.

Name-normalization caution: Google Patents lists the 1996 filing applicant as "Toshiba Corp, Konica Minolta Inc." That is a retroactive rename — Konica Minolta did not exist until 2003. At filing the co-assignee was Konica Corporation.

Assignment timeline

Two recorded assignment-type events. (Reel/frame and correspondent fields could not be retrieved — see source note.)

• 1996-10-28 (executed/recorded date as listed) / recorded 1996-10-28 — Reel unknown — not retrievable via open web search

  • Conveyance: Assignment (inventor→company; Google Patents tags it "reassignment," but it is the initial assignment)
  • Assignor: Saito, Shinichiro; Nakamura, Norio; Shono, Yasuo; Higuchi, Yoshinori; Ohyama, Atsunori (all five inventors)
  • Assignee: Konica Corporation and Toshiba Corporation (joint/co-ownership)
  • Correspondent: Not retrievable. Probable-but-unconfirmed: Frishauf, Holtz, Goodman, Langer & Chick (New York), the firm of record on the patent's prosecution per Justia — a single appearance would not by itself be an NPE tell, and I have no confirmation it filed the recording.
  • Context: Standard initial assignment of inventors' rights to the two co-developing operating companies.
  • Note on date ordering: the application was filed 1996-07-31, yet the recorded assignment date is 1996-10-28 (≈3 months post-filing). This is consistent with a typical "assignment recorded shortly after filing" sequence, not a red flag.

• 2005-11-14 (executed/recorded date as listed) / recorded 2005-11-14 — Reel unknown — not retrievable via open web search

  • Conveyance: Assignment
  • Assignor: Konica Minolta Holdings, Inc. (corporate successor to Konica Corporation)
  • Assignee: Toshiba Corporation (sole owner thereafter)
  • Correspondent: Not retrievable.
  • Context: Internal/portfolio consolidation — Konica's corporate successor exited its 50% co-ownership, leaving Toshiba as sole owner. This is a two-party de-risking of a jointly-held patent, not a transfer to an asserter.

No other recorded conveyances (no security agreement, merger, license, release, correction, or change-of-name records) are reflected in the available event data. If the Assignment Center shows a Konica→Konica Minolta change-of-name recording (expected around the 2003 merger), it was not surfaced in my sources and should be verified.

Timeline diagram

timeline
    title Ownership of US 5779337
    1996 : Filed by Konica and Toshiba
         : Inventors assign to both cos
    1998 : Patent granted
    2003 : Konica becomes Konica Minolta
    2005 : Konica Minolta stake to Toshiba
    2016 : Patent expired

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. No assignee bears an "IP / Patents / Licensing / Holdings / Ventures" licensing-only profile. The 2005 assignee (Toshiba Corporation) is an operating company; the 1996 assignees are two operating manufacturers. No single-purpose Delaware/Texas LLC appears.

2. Known asserter in the chain — Not present. Correcting the litigation section's note: the "Holdings" in Konica Minolta Holdings, Inc. is a genuine Japanese operating-company group holding structure (2003 merger vehicle), not a US NPE. No match to Acacia, Marathon, IV, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Round Rock, MPHJ, Lumen View, etc.

3. Repeat correspondent across the chain — Unclear (data gap). Correspondents of record were not retrievable. Frishauf, Holtz, Goodman, Langer & Chick appears as the patent's prosecution firm (Justia), but a single firm appearance is not an NPE finding, and I have no confirmation it recorded either assignment. Marking unclear, not present.

4. Cascading transfers — Not present. Only two assignments across nine years (1996 → 2005), with ~9 years between them. No chain of LLCs in <24 months; no shared correspondent-address pattern observable.

5. Pre-litigation transfer — Not present. Per the litigation analysis, no infringement suit naming this patent was found. There is therefore no 6-month pre-suit transfer to anchor. (Caveat: absence of litigation is a negative finding, not certified proof.)

6. Bankruptcy fire-sale — Not present. No Chapter 7/11, no insolvency-sale conveyance. The 2005 transfer was a pre-scandal, ordinary co-ownership unwinding (Toshiba's 2015+ travails post-date it by a decade).

7. Privateering — Not present. No operating-company→NPE transfer; the chain moves toward an operating company (Toshiba), the opposite of privateering.

8. Defensive aggregator (anti-NPE) — Not present. Chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. (Toshiba is a LOT Network founding member, but the patent itself was never conveyed into LOT or any aggregator, and it expired in 2016 — so no neutralization event to cite.)

Verdict

Defensive / non-asserting — with a stated caveat.

Justification: The recorded chain is a clean, two-step co-ownership consolidation: inventors → Konica Corporation + Toshiba Corporation (recorded 1996-10-28), then Konica Minolta Holdings, Inc. → Toshiba Corporation (recorded 2005-11-14), leaving a single operating-company owner. No shell entity, no known asserter, no cascading LLC transfers, no fire-sale, and no litigation (per the litigation section) appear — so none of the NPE verdicts fit. The terminal holder is an operating company, not a defensive aggregator, and the patent expired 2016-07-31; it was never asserted, so it was effectively neutralized by simple market non-use. I therefore select the non-asserting bucket while flagging that the literal "defensive aggregator" trigger does not apply. Net finding: no NPE / troll pattern; a dormant, operating-company-owned patent.

Verification link: USPTO Assignment Center — search patent 5,779,337 (application 08/691,807). Retrieve reel/frame and correspondent fields there to close the two data gaps flagged above.

Residual gaps (explicit): (a) reel/frame numbers for both assignments; (b) recorded correspondent names; (c) any Konica→Konica Minolta change-of-name recording. None of these were fabricable and none were obtained.

I'll research the prior-art references cited in US 5,779,337, focusing on the front-page "References Cited" data.

Let me pull the complete cited-reference list from the patent's front page.

Let me get the foreign references and the complete citation list.

I hit the tool-call limit while retrieving the full foreign-reference list, so I'll report what I verified and flag precisely what remains unretrieved.

Prior Art Analysis — US 5,779,337

A. Method and important scope note

You asked me to find the prior art cited in US 5,779,337 (i.e., the Examiner/applicant "References Cited" on the face of the patent) and assess § 102 potential. Two clarifications are essential before the table:

1. "Prior art cited in 5779337" ≠ "references that cite 5779337." My searches surfaced many forward citations — later documents that cite US 5,779,337 as their own prior art (e.g., WO 2006133458 A3 to UBright Optronics, where US 5,779,337 is graded "X" for claims 1 and 9; EP 1764548 A3; EP 2523025 A3; EP 1944630 B1). Those are not part of the prior art examined against US 5,779,337, and I exclude them from the anticipation analysis below. A companion note: "5779337" as a bare string also matches JP 特許第5779337号 (General Electric, "rotary valve assembly for high-temperature and high-pressure operation," granted 2015‑09‑16) — an unrelated document. I did not conflate it.
2. Completeness caveat. The only front-page "References Cited — U.S. Patent Documents" list I could retrieve (Justia) is truncated (it shows three entries followed by an ellipsis). I therefore cannot certify that this is the complete list of cited U.S. patents. The three U.S. references below are verified; additional cited references may exist that I could not retrieve.

B. Verified prior-art references cited in US 5,779,337

U.S. Patent Documents (verified from the patent's "Referenced Cited" table)

Foreign / non-patent references cited (from the specification body)

The specification expressly discusses two Japanese publications as the closest prior art, so they are necessarily cited art:

Uncertainty flag: I could not retrieve the patent's printed "Foreign Patent Documents" bibliography (the formal front-page list). The two Japanese publications above are confirmed from the patent's own description; there may be additional cited foreign documents I did not recover.

C. Which claims the cited art realistically threatens

• Independent claims 1, 22, 33 (structural genus: edge lamp + light guide with parallel emitting-face projections/grooves): the cited art (US 5,485,291 / 5,485,354 / 5,575,549 and JP U.M. 6‑16902) supplies every element except the point of novelty — the requirement that the height/depth of each projection/groove increase from the central portion toward the two end portions in the lamp's longitudinal direction. That limitation is the acknowledged basis for allowance. § 102 anticipation of these independent claims is doubtful; the cited art is better characterized as § 103 material.
• Dependent claim 14 / 19 (prism-like, no undercut): the patent affirmatively distinguishes JP U.M. 6‑16902 (which has an undercut), so this claim is even more clearly non-anticipated by that reference.
• Area-ratio/pitch dependent claims (projection area ratio differing near vs. far from the lamp; pitch ≤ 200 µm — claims 2/3, 17, 23/24): these are the claims most exposed to a § 103 combination of the cited U.S. references (particularly US 5,575,549, which already teaches feature size increasing with distance from the light source) plus the JP U.M. 6‑16902 pitch gradient.
• Diffusion/collimation dependent claims (convergence coefficient 2–4, haze 70–95%, one or two diffusion sheets, aligned prism collimation sheet): not addressed by the structural cited art; these were presumably supported as conventional optical adjuncts.

D. Confidence and limits

• High confidence: the three U.S. references and their publication dates (from the patent's own "Referenced Cited" table); the two Japanese publications (from the patent's description); the "longitudinal height/depth taper" being the point of novelty.
• Medium confidence: the technical characterization of US 5,485,291 and US 5,485,354 (I could not retrieve their titles/assignees within budget — do not rely on the descriptions above without checking the documents themselves). US 5,575,549's disclosure is high confidence (its "Surface light source device" text was retrieved directly).
• Not retrieved: the complete front-page "References Cited" list (Justia truncated it) and the formal "Foreign Patent Documents" bibliography. A definitive study requires pulling the full patent PDF front page and the USPTO file wrapper (Image File Wrapper) for application 08/691,807.
• No § 102 rejection can be asserted as fact. These are references the Office/Applicant placed of record; the patent issued over them, so none was treated as anticipatory during prosecution.

Bottom line: The verified prior art cited in US 5,779,337 comprises U.S. 5,485,291, 5,485,354 and 5,575,549, plus JP U.M. Kokai 63‑24529 and JP U.M. Kokai Hei 6‑16902. The closest reference is JP U.M. Kokai Hei 6‑16902 (expressly distinguished), and the most structurally relevant U.S. reference is US 5,575,549 (Enplas). None of these appears to disclose the claimed increase in projection/groove height (depth) from the lamp's central portion toward its two end portions, which is why independent claims 1, 22 and 33 are unlikely to be anticipated and should be analyzed under § 103 instead.

I'll ground this analysis in the actual prior-art references tied to this patent. Let me pull the cited references and the two Japanese Utility Model publications discussed in the patent's own "Description of the Prior Art."

I have the key prior-art references. Let me pull the substance of each cited U.S. reference, since these are the references actually on the patent's face.

Obviousness Analysis — US 5,779,337 under 35 U.S.C. § 103

Scope note. This § 103 analysis builds on — and does not repeat — the bibliographic, claim-summary, litigation, and PTAB sections already generated. It uses the prior-art material identified on/for this patent: (i) the two Japanese Utility Model publications discussed in the patent's own "Description of the Prior Art," (ii) the U.S. references listed in the patent's "References Cited" (retrieved in part from the Justia copy at https://patents.justia.com/patent/[5779337](/patent/5779337)), and (iii) the admissions about the prior art that the applicants make in the specification. Because the Google Patents text supplied for this analysis omits the front-page "References Cited" table, the U.S. reference list below is partial and should be re-verified against the printed patent front page before being relied on in a filing.

1. The prior art of record

Admissions in the specification (usable as prior art under § 103 via the applicant's own characterization): the patent concedes that (a) tubular lamps have "non light‑emitting electrodes at each edge portion," producing "light‑emission irregularity … in the longitudinal direction," and (b) the solution to non‑uniform extraction is spatial modulation of the extraction features (FIGS. 1–2 discussion). Both admissions save the examiner/petitioner the work of finding an express reference for the lamp end-darkening problem.

Note / contradiction flag (per your instructions): An earlier generated section said US 5,779,337 is cited as an "X" reference in EP 1 764 548 A3. The EPO search-report text I retrieved for EP 1 764 548 A3 lists it as category "[A]" (background) — see http://data.epo.org/pise-server/rest/collections/lgpi/EP1764548A3.pdf. That earlier characterization appears inaccurate and should be corrected. Separately, US 5,779,337 is described in EP 1 944 630 B1 as teaching "light guiding devices having projections, grooves or prismatic structures for emitting light" (https://patentimages.storage.googleapis.com/bc/97/05/c66dff5330c675/EP1944630B1.pdf) — useful evidence of how the art itself characterizes the disclosure.

Second contradiction flag: The earlier summary states the patent has 33 claims. The retrieved Justia text contains "38. A light guide according to claim 36," which implies at least 38 claims and a different independent-claim numbering than assumed (likely claims 1, 22, 33/34, and 36 are the independents). Treat the "33 claims" figure as unverified. This matters for a claim-by-claim § 103 challenge: the dependent claim numbers in any ground of rejection must be re-checked against the printed claims.

2. Governing standard

The application was filed 1996‑07‑31 with a 1996‑05‑13 JP priority, so pre‑AIA §§ 102/103 apply. At issue in 1998 the Federal Circuit applied the teaching‑suggestion‑motivation ("TSM") test, which was then relaxed by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), and the rationales codified at MPEP § 2143. A modern validity challenge is judged under KSR, i.e., the whole of a POSITA's knowledge, design incentives, and "obvious to try" with a finite number of predictable solutions — not a rigid requirement of express teaching.

The field is highly predictable. Light guides are governed by Snell's law and total internal reflection; the patent itself says the prior art guide "is designed to use substantially only reflection and refraction." Where the operative art is predictable, the Federal Circuit and the Board routinely find combinations obvious, and the patent's own numeric design rules read as routine optimization rather than invention.

3. Claim decomposition

Independent claim 1 (unit, projections). Element (a) tubular lamp; (b) light guide with incident face, reflecting face, emitting face; (c) plurality of projections on the emitting face, running parallel to each other along the lamp's longitudinal direction, that extract light from the emitting face; and (d) — the point of novelty — each projection is taller at its two ends than at its middle, measured along the lamp axis.

Independent claim 22 (unit, grooves). Same as claim 1 except the extraction features are grooves and the depth, not height, increases center→ends.

Independent light-guide claims (≈33/34 and ≈36). Same structure, claimed as the plate alone.

Numeric / structural dependents. projection‑area‑ratio A: 15 < A < 20 for 100 < L < 162; 11 < A < 15 for 220 < L < 270; formation‑ratio Rx windows S(x)±5 and S(x)±3; average pitch ≤ 200 µm; diffusion means (convergence coefficient 2–4; haze 70–95 %; one or two sheets) with the luminance peak held within 30° of normal; collimation sheet whose prisms align with the projection array; prism‑like, undercut‑free projection; and 3.0 > base/height > 1.0.

4. Ground 1 (strongest): JP HEI 6‑16902 + JP 63‑24529 + the admitted lamp end‑darkening

Claim chart — claim 1.

Why the combination is obvious. The only missing element (the height gradient along the lamp's length) is the solution to a problem the patent itself attributes to the lamp, not to the guide: "non light‑emitting electrodes at each edge portion of the tubular light source … light‑emission irregularity … is caused in the longitudinal direction." A POSITA confronting end‑darkened lamps has a known problem, a finite set of known variables (feature height, width, base pitch, or extraction density), and a known principle ([A]) for applying them: extract more light where less light is available. Selecting height from that finite menu is the paradigm KSR case of "obvious to try." MPEP § 2143 rationales apply squarely:

• Known technique to improve a similar device in the same way. [A] modulates extraction in the propagation direction; [B] already modulates pitch in the propagation direction. Extending spatial modulation to the orthogonal (lamp‑longitudinal) axis is the same technique applied to the same class of device.
• Obvious design need / market pressure. LCD backlights demanded uniform luminance; lamp end‑darkening was a recognized, unsolved uniformity defect.
• Predictable result. Making prisms taller at the ends monotonically raises the local extraction cross‑section; the result (flatter luminance along the lamp) is exactly what the mathematics of an integrating plate predicts.

Claim 22 (grooves) falls to the same combination, because [B] is a projection reference but [C] US 5,485,291 is a groove reference, and a groove is the geometric inverse of a ridge; substituting a recess for a projection to achieve the identical extraction function is a simple substitution of one known element for another (KSR; MPEP § 2143). [B]+[C]+[A] therefore renders claim 22 obvious with an even shorter chain, because [C] supplies the edge‑lit, groove‑faceted, reflecting‑surface‑backed guide and [A] supplies the modulation principle.

Claims to the bare light guide (≈33/34, 36) are obvious a fortiori: they recite the same physical article with no additional element beyond structure already disclosed by [B] and [C].

5. Ground 2 (alternative primary reference): US 5,485,291 + JP HEI 6‑16902

[C] Qiao discloses, in an edge‑lit plate: a shaped surface carrying faceted grooves whose two facet families have deliberately unequal slopes (1°–15° toward the lamp; 35°–55° away), a reflecting surface behind the shaped face, a lamp at one or both ends, groove depths of 5–10 µm, and land widths between 1 and 200 µm. [C] thus discloses nearly the whole of the structural genus of claim 22 (grooves) and, read with [B]'s parallel‑to‑the‑lamp orientation, of claim 1.

A POSITA combining [C]'s faceted‑groove extraction with [B]'s teaching-directed, lamp‑parallel prism array, and then applying the admitted end‑darkening compensation by deepening the grooves toward the lamp ends, arrives at claim 22 without invention. Motivation: both references are in the same field (edge‑lit LCD backlights), address the same problem (uniform, high‑efficiency extraction), and [C] itself already varies a geometric extraction parameter positionally — the step of varying it along the second axis to compensate the source is the natural next step.

6. Ground 3: the dependent claims

• Average pitch ≤ 200 µm. [C] expressly discloses land widths of 1–200 µm, which reads directly on (and provides the motivation for) the ≤ 200 µm pitch limit; [B] teaches that pitch is a design knob. Sub‑200 µm pitch is also the admitted reason a diffusion sheet can be omitted (fringes below visible resolution) — an obvious design choice.
• Undercut‑free, prism‑like projection. [B]'s projection 3005 has an undercut face 3053, which the patent says requires a slide mold and is "not suitable for mass production." Removing the undercut to enable a simple two‑part mold is a manufacturing‑driven, predictable modification — the classic "improve the device by eliminating a known manufacturing drawback." Against this, the patent owner may argue that deleting the undercut sacrifices the optical function of [B]; that is a teaching‑away / changed‑principle argument (see § 8).
• base/height between 1.0 and 3.0. Pure geometric optimization of a prism cross‑section to balance extraction efficiency against moldability — routine experimentation, no criticality shown.
• Diffusion means; haze 70–95 %; convergence coefficient 2–4; one or two sheets; peak within 30°. The patent's own FIG. 1 prior art already includes a diffusion sheet 2007 and a collimation sheet 2009; diffusion sheets in edge‑lit backlights were ubiquitous by 1996, and the specification identifies two off‑the‑shelf products ("DF‑100," haze 90 %, convergence coefficient 2.5; "D119") as suitable. Choosing a sheet whose haze falls in 70–95 % and whose convergence coefficient falls in 2–4 is selecting a known material with known properties and predictable results, and the stated reason (viewing‑angle quality, avoiding moiré) is an articulated, predictable benefit. These dependents are the weakest of the set.
• Collimation sheet with prisms aligned to the projection array. Again disclosed in kind by the FIG. 1 prior art; the specification even admits the alignment direction may be slightly skewed for anti‑moiré tuning, i.e., a matter of routine design. Use of 3M "BEF II" is conventional.
• Numeric area‑ratio/formation‑ratio windows (15<A<20 for 100<L<162; 11<A<15 for 220<L<270; Rx within ±5 / ±3 of S(x)). These are the most attackable targets — and the patent owner's best defensive ground. See § 8.

7. The strongest "motivation to combine" statement, in one paragraph

A person of ordinary skill in 1996 — an LCD‑backlight optical engineer — knew three things: (1) prism/faceted light guides extract light with high efficiency and without the absorption loss of a printed scatterer ([B], [C]); (2) the amount of light travelling down a plate falls with distance from the lamp, so extraction must be increased with distance ([A], [B]); and (3) a tubular lamp is dimmer at its two ends because of its non‑emitting electrodes (an admitted, ubiquitous fact). Given (1)–(3), making the extraction features taller/deeper toward the two ends of the lamp is a predictable application of a known principle to a recognized defect, using a finite and fully enumerated set of design variables (height, depth, width, pitch, density). KSR and MPEP § 2143(a)–(g) supply multiple independent rationales, and no reference teaches away.

8. Counterarguments the patent owner will raise (and their strength)

1. No reference discloses height variation along the lamp axis. (Moderate.) True as a literal matter, but KSR does not require it; the variation of a known extraction parameter to cure a known non‑uniformity is enough. Still, this is the factual gap a petitioner must close with either (a) art showing feature‑size variation along the lamp axis, or (b) a declaration that the parameter choice was a design choice among a finite set.
2. Criticality of the numeric windows — the specification's own data. (Strong for claims 12/17 and their Rx counterparts.) The specification reports that a comparative guide with A = 20.4 % (just above the 15<A<20 window) exhibited luminance irregularity of 48.9 %, while A = 17.7 % was uniform, and A = 14.8 % produced a luminance drop far from the lamp. If the patentee can establish nexus between these numbers and a commercial product, this is a colorable unexpected‑results / criticality showing. Expect a petitioner to answer that the trend is continuous and monotonic (extraction ∝ distance), so the "window" is merely the region where the well‑known balance is struck — i.e., routine optimization — and that the comparative data show the trend, not a surprise.
3. Secondary considerations generally. (Weak.) The asserted advantage — 1,300 cd/m² vs 1,100 cd/m² — is a degree‑of‑performance difference that flows from the claimed geometry and is not tied by evidence to any commercial embodiment; there is no copying or industry‑praise evidence in the record. The 2005 reassignment of the Konica interest to Toshiba suggests internal portfolio consolidation rather than market validation, and the patent's 2016 expiration removed any licensing engine.
4. Teaching away from removing the undercut. (Moderate, limited to the undercut claim.) [B]'s three‑facet design intentionally uses the undercut face optically; a petitioner must show that an undercut‑free prism of comparable function was known or conventional.

9. Procedural posture that shapes the analysis

• Pre‑AIA § 103 is the substantive law; KSR is the current standard.
• Because the patent expired 2016‑07‑31 (cross‑referencing the PTAB/litigation sections), an IPR remains legally available but yields only past‑damages relief, and ex parte reexamination (no estoppel, low cost) is often the more efficient vehicle — see the earlier "Recommended next steps." No PTAB or court estoppel exists, so every § 102/§ 103 ground above and any art the patentee did not consider remains available.
• Sequence matters: if the patent is ever re‑asserted, an IPR is time‑barred one year from service of a complaint (§ 315(b)), so a pre‑suit invalidity study built on Ground 1 is the highest‑value spend.

10. Verification flags (do not rely on these without checking)

1. Full front‑page reference list for US 5,779,337 was not available in the supplied text; the U.S. references in § 1 come from a partial Justia listing and may be incomplete (foreign patent documents and additional U.S. patents likely appear on the printed face).
2. US 5,485,354 (Ciupke) content unverified — I could not retrieve its disclosure this session; it is listed only because it appears on the patent's face. Do not build a ground on it until its text is read.
3. US 5,575,549 (Ishikawa) issued after the filing date; it is § 102(e) art only if its U.S. filing date precedes 1996‑05‑13. Its filing date is unverified.
4. Claim count/numbering conflict — "33 claims" (earlier section) vs. a "claim 38 depending on claim 36" in the retrieved text. Re‑number before filing any rejection.
5. EP 1 764 548 A3 citation category — earlier section said "X"; retrieved EPO report shows "[A]." Correct the earlier statement.
6. The Google Patents "Prior art keywords" (light, projection, projections, emitting surface, light source) are algorithmic, not art, and carry no evidentiary weight.

Bottom line: Independent claims 1, 22, and the light‑guide claims are, on the record available here, vulnerable under § 103 to JP HEI 6‑16902 in view of JP 63‑24529 (with the lamp end‑darkening admitted) — and, for the groove claims, to US 5,485,291 in view of JP HEI 6‑16902. The mechanical dependents (pitch ≤ 200 µm, diffusion sheet, collimation sheet, undercut‑free prism, base/height ratio) are weakly supported, whereas the numeric area‑ratio/formation‑ratio windows are the patentee's real defensive position, supported by the specification's own criticality data — and are the claims a challenger should either avoid or attack head‑on as routine optimization.