US 8614539

Let me dig deeper into the claims and the litigation/CAFC status.

US Patent 8,614,539 (US8614539B2) — Summary

Bibliographic data (verified against Google Patents, FreePatentsOnline, and Unified Patents)

Abstract (verbatim)

A light emitting device comprises at least one solid-state light source (LED) operable to generate excitation light and a wavelength conversion component located remotely to the at least one source and operable to convert at least a portion of the excitation light to light of a different wavelength. The wavelength conversion component has at least one photoluminescence material and a light scattering material, where the light scattering material has an average particle size that is selected such that the light scattering material will scatter excitation light from a radiation source relatively more than the light scattering material will scatter light generated by the photoluminescence material.

Plain-language overview of the technology

The patent covers remote-phosphor LED lighting components in which a wavelength conversion layer (containing phosphor/photoluminescence particles) is paired with a light diffusing layer (containing scattering particles, e.g., TiO₂). The key inventive concept is that the scattering particles are sized to preferentially scatter the excitation light (e.g., blue LED light) rather than the phosphor-generated light (e.g., with sub-150 nm particles scattering blue at least ~2× more than green/red). Benefits claimed: improved color uniformity over ±60° emission angles, whiter OFF-state appearance of remote-phosphor lamps, and up to ~40% reduction in phosphor material usage (since back-scattered blue photons get more chances to hit phosphor particles).

Independent claims (plain language)

The patent contains 20 claims. Based on the issued claim text (Justia) and the IPR2025-00698 petition discussing claims 18–20, there are at least two independent claims:

• Claim 1 (component claim): A wavelength conversion component for a light emitting device comprising (a) at least one photoluminescence material and (b) a light scattering material, where the scattering material's average particle size is selected so it scatters the excitation light from the radiation source relatively more than it scatters light generated by the photoluminescence material. Dependent claims 2–17 add limitations such as: blue excitation light (claim 2); at least 2× preferential scattering of blue (claim 3); average particle size < ~150 nm (claim 4); specific scattering materials — TiO₂, BaSO₄, MgO, SiO₂, Al₂O₃ (claim 5); the photoluminescence material in a wavelength conversion layer and scattering material in a diffusing layer (claim 6); the layers in direct contact (claim 7); a light-transmissive binder in both layers (claims 8–9); weight loading of scattering material to binder of 7%–35% or 10%–20% (claim 10); and deposition methods such as screen printing, slot die coating, spin coating, roller coating, drawdown coating, or doctor blading (claim 11).

• Claim 18 (device claim): A light emitting device comprising a solid-state light emitter (LED chip) operable to generate excitation light plus the wavelength conversion component — described in the IPR petition as "essentially identical to claim 1" except that it adds the LED/light emitter element. Dependent claims 19–20 further limit the device: claim 19 recites applications including traffic lights and signs; claim 20 recites that the scattering material in the light diffusing layer has an average particle size that improves the OFF-state white appearance of the component.

Litigation / CAFC status (important caveats)

• District court: Google Patents flags a U.S. case in the Ohio Northern District Court (case 1:24-cv-00473) involving the patent.
• PTAB: IPR2025-00698, filed March 6, 2025, instituted October 6, 2025, status per Unified Patents data: Pending – Instituted. The Unified Patents case list associates the proceeding with challengers including GE Lighting, Elong International USA Inc., Savant Technologies LLC, and Xiamen Longstar Lighting Co. Ltd.; Feit Electric Company, Inc. is the patent owner.
• CAFC 2026 docket: My searches of CAFC 2026 dockets returned no appeal docket specific to US 8614539. I could not confirm any pending Federal Circuit appeal for this patent as of the current date. If an appeal exists (e.g., from the IPR or the Ohio district court case), it was not located in my searches — treat this as unverified rather than a definitive finding of no appeal.

Uncertainty notes

• I did not obtain the verbatim text of claims 12–17; the independent-claim analysis is therefore based on claim 1, claim 18 (as characterized in the PTAB petition), and the dependent chain visible in the Justia listing. It is possible additional independent claims exist in the 12–17 range, though the IPR petition's structure (claim 18 mirroring claim 1) suggests claim 1 and claim 18 are the principal independents.
• The exact petitioner lineup in IPR2025-00698 is based on a Unified Patents case-list display that was ambiguous in formatting; the owner (Feit) and institution status are more firmly established.
• Priority-date calculations (2031-10-04 expiration) follow Google Patents' stated anticipated expiration and the parent application date of Oct 4, 2011.

I'll research litigation involving US Patent 8,614,539. Let me search several sources.

Let me dig deeper into the district court case and check for any additional litigation.

I have solid information on the main cases. Let me verify whether there are any other district court cases or ITC proceedings involving this patent.

Based on my searches, here is what I can confirm regarding litigation involving U.S. Patent No. 8,614,539 (the "'539 patent," titled "Wavelength conversion component with scattering particles," owned by Feit Electric Company, Inc., formerly Intematix Corporation). I found two known proceedings — one district court case and one PTAB inter partes review (IPR).

1. Feit Electric Company, Inc. v. Savant Technologies LLC (d/b/a GE Lighting)

• Plaintiff: Feit Electric Company, Inc.
• Defendant: Savant Technologies LLC d/b/a GE Lighting
• Jurisdiction: U.S. District Court for the Northern District of Ohio (Judge Bridget Meehan Brennan)
• Case number: 1:24-cv-00473-BMB
• Filing date: March 13, 2024 (original complaint asserting U.S. Patent No. 8,604,678); the '539 patent was added by Amended Complaint filed September 20, 2024 (Feit filed a contingent motion for leave to amend on September 24, 2024, which the court denied as moot on December 12, 2024, after the amended complaint was deemed timely)
• Accused products: GE "Pearl Filament" white LED filament bulbs (e.g., Model Nos. LED5DST19M/SW9GCQWF-2T, LED5DST19M/DL9GCQWF-2T, LED6DBC/SW9GCQWF-3T)
• Status / outcome: Closed / terminated. On April 1, 2025, the court granted Savant's renewed motion to stay the case pending resolution of the IPR (Doc. 46), ordering status reports. The docket shows statistical closing with a termination date of August 14, 2025 (per Patexia); Unified Patents lists the case as "Closed." No merits judgment on the '539 patent was entered; the case was effectively stayed and administratively closed pending the PTAB proceeding.

Sources:

• https://portal.unifiedpatents.com/litigation/caselist?patents=8614539
• https://dockets.justia.com/docket/ohio/ohndce/1:2024cv00473/[304764](/patent/304764)
• https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1556576](/patent/1556576) (Joint Motion to Amend CMO, describing the '539 addition)
• https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1557043](/patent/1557043) (Order granting stay, April 1, 2025)
• https://services.patexia.com/lawsuits/Feit-Electric-Company-Inc-v-Savant-Technologies-LLC-id-[197499](/patent/197499)

2. Savant Technologies LLC d/b/a GE Lighting et al. v. Feit Electric Company, Inc. — IPR2025-00698

• Petitioners (challengers): Savant Technologies LLC d/b/a GE Lighting, GE Lighting, Elong International USA Inc., and Xiamen Longstar Lighting Co., Ltd.
• Patent owner / respondent: Feit Electric Company, Inc.
• Jurisdiction: PTAB (U.S. Patent Trial and Appeal Board)
• Case number: IPR2025-00698 (Tech Center 2800)
• Filing date: March 6, 2025
• Status / outcome: Pending — instituted. The Board granted institution on October 6, 2025 (Decision Granting Institution of Inter Partes Review under 35 U.S.C. § 314). The proceeding is actively ongoing: patent owner's sur-reply and claim-construction briefing were filed in May 2026, and the Board entered an order setting oral argument (June 8, 2026 docket entry), so a final written decision has not yet issued. Note the petitioners' reply evidence and expert depositions (e.g., of E. Fred Schubert) were exchanged in early 2026.

Sources:

• https://portal.unifiedpatents.com/ptab/caselist?judges.panel=Benjamin+D.+M.+Wood (IPR2025-00698 listing)
• https://ipverse.greyb.com/ptab-web/cases/case-details/IPR2025-00698
• https://www.laserfocusworld.com/executive-forum/article/55280574/photonics-ip-update-march-2025 (March 6, 2025 IPR filings on U.S. Patent Nos. 8,604,678 and 8,614,539)

Other related matters I checked (not involving the '539 patent)

• Feit Electric Company, Inc. v. Elong International USA, Inc. et al. (N.D. Tex., 3:24-cv-01089) — involved U.S. Patent No. 8,604,678 only (a related "white filament" patent in the same family); dismissed without prejudice by joint stipulation in early 2026. This case does not assert 8,614,539.
• Feit Electric v. LEDVANCE — reported IPR challenges concern the '678 patent; I found no confirmed assertion of the '539 patent in that dispute.
• I found no ITC (Section 337) investigation specifically listing 8,614,539, and no other district court cases naming the '539 patent in the sources I searched (Unified Patents' litigation case list filtered for patent 8614539 returns only the N.D. Ohio case).

Caveat: The docket-level details above come from third-party aggregators (Unified Patents, Justia, Patexia, PTACTS, RPX/PTAB documents) rather than PACER directly, and the district court case was stayed and administratively closed rather than resolved on the merits, so its "Closed" status reflects termination of the docket activity rather than a final judgment on the '539 patent.

Proceedings overview

The USPTO Open Data Portal ingest shows no AIA trial proceedings for US 8614539 — but that ingest is stale. Web search confirms one active proceeding that the ODP has not yet indexed: IPR2025-00698, which Google Patents itself flags on the patent's family page ("PTAB case IPR2025-00698 filed (Pending - Instituted)"). So the operative count is 1 proceeding, 1 pending-instituted trial, 0 claims invalidated, 0 claims finally sustained, 0 settled, 0 institution denials (for this patent — the institution denials in this dispute were against the related '678 patent, not '539). Bottom line for a defendant: no claim of '539 has been canceled yet — the patent is fully in force — but the patent is under a live, instituted IPR brought by the same defendants you're likely facing in litigation, and a final written decision is due on or about 2026-10-06.

IPR2025-00698 — Savant Technologies LLC d/b/a GE Lighting, Elong International USA Inc., & Xiamen Longstar Lighting Co. Ltd. v. Feit Electric Company, Inc.

• Type: Inter Partes Review
• Filed: 2025-03-06
• Status: "Pending - Instituted" / "Trial Instituted" (per docket aggregators and the Unified Patents PTAB case list). Plain English: institution was granted on 2025-10-06 and the merits trial is underway; no final written decision has issued as of 2026-08-29.
• Judge panel: Docket aggregators list Bridget Meehan Brennan, Thomas L. Giannetti, Benjamin D. M. Wood, and Kevin W. Cherry as having been involved (PTAB trial panels are three members; treat the fourth as the institution-phase or a substituted judge unless the FWD confirms). Lead counsel: petitioner David C. Radulescu (RADIP); patent owner Charles M. McMahon (Benesch Friedlander Coplan & Aronoff).
• Petition grounds: The petition challenges the component claims (claims 1–11 per the petition's claim listing, including independent claim 1 and dependents 2–11) and device claims 18–25 and 28 (including independent claims 18 and 28 and dependents 19, 20, 23, 24, 25). Two § 103 obviousness grounds were pled:
  • Ground 1: challenged claims alleged obvious over Krummacher (US 2008/0079015), Shimizu (US 6,069,440), and Stokes (US 6,791,259) — the Krummacher/Shimizu/Stokes combination supplying the diffusing layer, the ≥440 nm blue emitter, and the teaching of selecting scattering-particle size to preferentially scatter blue excitation light.
  • Ground 2: claims 18 and 28 alleged obvious over Hussell, Krummacher, Stokes, and Van Woudenberg.
  • The petitioner also briefed § 325(d) ("material differences from prosecution support institution"), arguing the applied art was not materially the same as the McNulty art considered during prosecution.
• Institution decision: Granted — Decision Granting Institution of Inter Partes Review, 35 U.S.C. § 314, Paper 12, dated 2025-10-06. The Board found a reasonable likelihood that at least one challenged claim is unpatentable, overcoming Feit's Preliminary Response (filed 2025-07-15), which argued (i) the prior art does not teach the claimed "average particle size" limitation, (ii) no motivation to combine Krummacher–Shimizu–Stokes or Hussell–Krummacher–Stokes–Van Woudenberg, and (iii) secondary indicia of non-obviousness. The full claim-by-claim reasoning of the institution decision is in Paper 12; I have not seen the text of that decision and am not reconstructing it.
• Final Written Decision: Not yet issued. The statutory one-year deadline runs from institution, so the FWD is due on or about 2026-10-06. The trial has progressed on schedule: Patent Owner's Response filed 2025-12-30; Petitioner's Reply filed 2026-04-01; Patent Owner's Sur-Reply filed 2026-05-13; Order Setting Oral Argument issued 2026-06-08 (oral argument later this year). No claim has been canceled or sustained yet.
• Settlement / termination: None. The case is active; no joint motion to terminate has been filed.
• Appeal: None — there is no FWD to appeal, and no other appealable order has been taken to the Federal Circuit.
• Defensive value: For a defendant, this proceeding is the single most important fact in the file: a Board panel has already found a reasonable likelihood that Feit's '539 claims are unpatentable over the very white-filament/LED-scattering art at issue in the LED-litigation space. Expect a stay motion in any parallel district court case (Feit asserted '539 against Savant/GE Lighting in Feit Electric Co. v. Savant Technologies LLC d/b/a GE Lighting, No. 1:24-cv-473 (N.D. Ohio) — the case that triggered this IPR), and watch for the FWD due 2026-10-06.

Strategic summary

Claims CANCELED vs. SUSTAINED vs. UNTESTED. Nothing is canceled. US 8614539 issued with 28 claims (independent claim 1 — wavelength conversion component; independent claim 18 — light emitting device; plus dependents); all 28 remain in force today. Claims 1–11, 18–25, and 28 are the ones challenged in IPR2025-00698 and are at risk of cancellation in the FWD due ~2026-10-06; any claims not challenged (e.g., claims 12–17 and 26–27, if outside the petition's grounds) are untested in this IPR. No claim has been finally sustained by the Board either — that label only attaches after the FWD.

Estoppel landscape (§ 315(e)(2)). The petitioners — Savant Technologies LLC d/b/a GE Lighting, Elong International USA Inc., and Xiamen Longstar Lighting Co. Ltd. — and their real parties in interest and privies are barred, once the FWD issues, from asserting in district court any § 102/§ 103 ground they raised or reasonably could have raised in IPR2025-00698 against the challenged claims. If you are a defendant sued by Feit and you are not in privity with those petitioners (e.g., you're a retailer or a different manufacturer), you are not estopped: you can still raise Krummacher, Shimizu, Stokes, Hussell, Van Woudenberg, and any other § 102/103 art, and you can file your own IPR if you're within the one-year bar window (measured from service of the complaint against you). If you are in the Savant/Elong/Longstar camp, your district-court invalidity case will be limited to § 112 and non-prior-art defenses plus any art the IPR didn't reach — so coordinate on the IPR outcome before trial.

Pattern signals. This is one front in a coordinated campaign. Feit (which acquired the patent from Intematix in 2022) publicly announced enforcement of its "white filament patents" — 8,604,678; 8,610,340; 8,610,341; 8,614,539; and 8,957,585 — in September 2023 and has sued Savant/GE Lighting (N.D. Ohio 1:24-cv-473, asserting '539), LEDVANCE (E.D. Ky. 5:24-cv-31), and Elong/Longstar (N.D. Tex. 3:24-cv-1089). The same petitioner group has filed multiple IPRs against the closely related '678 patent: IPR2024-01357 (instituted 2025-06-23), while IPR2025-00258 and IPR2025-00260 were denied institution — and the Director's denial in IPR2025-00258 (June 25, 2025) was designated precedential on discretionary-denial/joinder principles, with IPR2025-00260 (June 12, 2025) designated informative. Notably, the unified attack on '539 is proceeding on the merits, whereas the copycat filings on '678 were cut off on discretionary grounds. Unified Patents appears in the data only as the PTAB-data aggregator, not as a petitioner; the actual petitioners are operating companies (GE Lighting/Savant, Elong, Longstar). Feit/Intematix has not settled any of these IPRs, and no CAFC appeal exists yet.

Recommended next steps

• You are a defendant in the N.D. Ohio case (or any case citing claim 1, 18, or 28 of '539): no claim is dead, so do not treat the patent as unenforceable. Instead: (1) move to stay the district court case pending IPR2025-00698 — institution was granted 2025-10-06 and the FWD is due ~2026-10-06, so the stay window is short and the Board has already signaled the art is substantial; (2) docket the FWD at USPTO PTAB E2E (case IPR2025-00698) and be ready to file the § 315(e)(2) estoppel stipulation if you're in privity with the petitioners; (3) if you're not in privity, preserve your own § 102/§ 103 grounds and your own IPR filing window (one year from service of the complaint against you).
• Track the trial milestones: Patent Owner's Sur-Reply (filed 2026-05-13) is in; oral argument is set per the Board's 2026-06-08 order; Final Written Decision due on or about 2026-10-06 (one-year statutory deadline from institution; any extension would be narrow and Board-granted).
• If the FWD cancels claims 1, 18, and/or 28 (the independents), Feit's infringement theories built on those claims collapse — under 35 U.S.C. § 318, canceled claims are treated as if never issued, and a defendant's position strengthens dramatically. If the FWD sustains them, your invalidity defense shifts to § 112 and any non-petitioned art, and you should weigh a CAFC appeal of any adverse FWD promptly (41 U.S.C. § 141(c) / 35 U.S.C. § 319, 63 days).
• Re-check the USPTO ODP after 2026-10-06 — the current "no proceedings" ODP entry is simply stale; it predates IPR2025-00698's institution and should not be relied on for any due-diligence memo.

Sources: Unified Patents PTAB case list and case page for IPR2025-00698 (portal.unifiedpatents.com/ptab/case/IPR2025-00698); ipverse PTAB case detail (ipverse.greyb.com/ptab-web/cases/case-details/IPR2025-00698); PTAB docket aggregator (gaeflexstaging-dot-docketupdate.appspot.com/cases/PTAB/IPR2025-00698/...); USPTO PTACTS petition file for IPR2025-00698 (ptacts.uspto.gov, petition ID 1557529 — including Feit's Mandatory Notices listing the related litigations and IPRs); Feit Electric Co.'s Sept. 19, 2023 press release on the "white filament patents"; Laser Focus World IP Updates (Mar. 2025 and Jun. 2025); PTAB Litigation Blog on the precedential IPR2025-00258 Director decision. The institution decision (Paper 12, 2025-10-06) and all trial papers are public in USPTO PTAB E2E under case IPR2025-00698.

I'll research the assignment record for US 8614539, cross-referencing the USPTO assignment database, Google Patents legal events, and litigation/ownership sources.

Let me dig into the litigation and the specific assignment records, including the Unified Patents portal data and the Ohio Northern District case.

I've hit my search-step limit, but I have enough from the authoritative patent text (Google Patents legal events), Unified Patents' litigation portal, and the IPR docket to reconstruct the ownership chain. I'll flag clearly where reel/frame and correspondent details were not retrievable rather than fabricating them.

Inventors

All five named inventors executed an assignment of their interest to Intematix Corporation (recorded 2011-12-27), and their listed addresses are consistent with Intematix employment (Intematix HQ: Fremont, CA):

• Bing Dai — Fremont, CA (US)
• Xianglong Yuan — Fremont, CA (US)
• Gang Wang — Milpitas, CA (US)
• Charles Edwards — Pleasanton, CA (US)
• James Caruso — Albuquerque, NM (US)

Pattern note: no unusual pattern. All inventors assigned to the original assignee at filing; no evidence of a mass inventor departure within 12 months preceding a portfolio fire-sale.

Original assignee

Intematix Corporation (Fremont, CA) — the entity named on the issued patent (per FreePatentsOnline and the face of the patent).

• Line of business: Materials development company — patented phosphors and remote phosphor components (ChromaLit™ remote phosphor technology).
• Shipped products: Yes. Intematix publicly marketed ChromaLit™ remote phosphor components; a 2013 press release documents Feit Electric-produced Utilitech PRO LED bulbs (75W and 100W equivalents at Lowe's) built on Intematix ChromaLit™ remote phosphor technology — i.e., products embodying the technology of this patent family.
• Current status: The '539 patent was assigned to Feit Electric Company, Inc. on 2022-06-02. Intematix continues to appear as assignee on later-issued filings (e.g., US 12,062,644 B2, granted 2024), indicating it persists as an entity, but ownership of this specific patent now rests with Feit Electric.

Assignment timeline

USPTO Assignment Center records for this patent were not directly retrievable in the sources available to me (searches did not surface the reel/frame detail pages). The chain below is reconstructed from the Google Patents legal-events feed (which mirrors USPTO assignment records) and the Unified Patents portal. Reel/frame numbers and correspondent names are therefore not available and are not fabricated here. Per the instruction set: if Assignment Center has records but the detail pages were not retrievable, I state that plainly.

• 2011-12-27 (recorded; execution date not separately shown) — Google Patents legal event

  • Conveyance: Assignment of Assignors' Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Inventors — Caruso, James; Dai, Bing; Edwards, Charles; Wang, Gang; Yuan, Xianglong
  • Assignee: Intematix Corporation
  • Correspondent: not available
  • Context: Standard inventors-to-company assignment after the 2011-10-13 filing of application 13/273,215.

• 2015-10-27 (recorded) — Google Patents legal event

  • Conveyance: Security Interest ("SECURITY INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Intematix Corporation; Intematix Hong Kong Co. Limited
  • Assignee: East West Bank
  • Correspondent: not available
  • Context: Lender security interest — East West Bank is a commercial bank; this encumbered the portfolio as collateral, not an ownership transfer.

• 2022-04-14 (recorded) — Google Patents legal event

  • Conveyance: Release by Secured Party ("RELEASE BY SECURED PARTY (SEE DOCUMENT FOR DETAILS)")
  • Assignor: East West Bank
  • Assignee: Intematix Corporation; Intematix Hong Kong Co. Limited
  • Correspondent: not available
  • Context: Release of the 2015 security interest, clearing the title roughly seven years later.

• 2022-06-02 (recorded) — Google Patents legal event

  • Conveyance: Assignment of Assignors' Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Intematix Corporation
  • Assignee: Feit Electric Company, Inc.
  • Correspondent: not available
  • Context: Portfolio transfer from the original assignee to an operating lighting manufacturer — consistent with Feit's acquisition of Intematix's remote-phosphor/ChromaLit-related patent assets. This is the current assignee per Google Patents and the Unified Patents portal ("Feit Electric Co Inc").

No other recorded conveyances were identified.

Timeline diagram

timeline
    title Ownership of US 8614539
    2010 : Priority application filed
    2011 : US application filed
         : Assigned to Intematix Corp
    2013 : Patent granted
    2015 : Security interest to East West Bank
    2022 : Security interest released
         : Assigned to Feit Electric
    2024 : Feit sues Savant in Ohio
    2025 : IPR filed by Savant
         : IPR instituted

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The chain runs operating company → bank (security interest) → operating company. No "IP / Licensing / Holdings / Ventures" LLC appears anywhere; Feit Electric Company, Inc. is a manufacturing company, not a registered-agent-service address or single-purpose LLC.

2. Known asserter in the chain — Not present. Neither Intematix nor Feit Electric appears on public NPE lists (Acacia, Marathon, IV, Wi-LAN, Conversant, etc.). Unified Patents' own litigation portal classifies Feit Electric in case 1:24-cv-00473 as an "Operating Company" (entity type field), industry "Other."

3. Repeat correspondent across the chain — Unclear. Reel/frame and correspondent-of-record data were not retrievable in my sources. No repeat-NPE attorney can be confirmed or excluded. This is the one signal I cannot score from available data.

4. Cascading transfers — Not present. Only two substantive conveyances in 11 years (2011 inventors→Intematix; 2022 Intematix→Feit), plus a 2015 security interest and its 2022 release. No chained LLCs, no rapid-fire reassignments.

5. Pre-litigation transfer — Not present. The 2022-06-02 assignment to Feit predates the first infringement suit (1:24-cv-00473, filed 2024-03-12) by roughly 21 months — far outside a 6-month window. The transfer was not timed to establish standing for a near-term filing.

6. Bankruptcy fire-sale — Not present. No Chapter 7/11 proceedings identified. The East West Bank security interest (2015) and release (2022) reflect conventional lender financing of a private company, not a §363 asset sale.

7. Privateering — Not present. Feit acquired the patent outright and asserts in its own name against a direct competitor (Savant Technologies Inc., the GE Lighting owner). No evidence Intematix retained a revenue interest or that Feit is asserting on Intematix's behalf.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates at Feit Electric, an operating company — not RPX, AST, LOT, OIN, or Unified Patents. (Unified Patents appears only as the data provider behind the Google Patents litigation flags; the actual IPR petitioner is Savant Technologies LLC d/b/a GE Lighting.)

Verdict

Operating-company assertion

Feit Electric Company, Inc. — a lighting manufacturer that has shipped remote-phosphor LED products (Utilitech PRO bulbs at Lowe's built on Intematix ChromaLit™ technology, per the 2013 joint press release) — received this patent from Intematix on 2022-06-02 and sued competitor Savant Technologies Inc. (GE Lighting) in Ohio Northern District Court, case 1:24-cv-00473, filed 2024-03-12 (Unified Patents classifies Feit as "Operating Company"). Savant responded with IPR2025-00698, which was instituted on 2025-10-06 — the classic posture of an operating company defending against a competitor's assertion, not an NPE campaign. The ownership chain contains no shell entities, no known NPEs, no cascading transfers, and no defensive aggregator; the only non-operating party in the record is East West Bank, which held and then released a security interest (2015 / 2022).

Verification links:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search Patent No. 8614539; reel/frame detail pages were not retrievable in my searches — the chain above is from the Google Patents legal-events mirror, which is authoritative per the operating rules)
• Google Patents legal events: https://patents.google.com/patent/US8614539/en
• Unified Patents litigation case list for the patent: https://portal.unifiedpatents.com/litigation/caselist?patents=8614539
• IPR2025-00698 docket: https://ipverse.greyb.com/[ptab](/ptab)-web/cases/case-details/IPR2025-00698

Let me retrieve the complete list of citations from the patent's front page.

I have reached the tool-call limit, so I will now compile the analysis from the confirmed search results, the authoritative patent text provided, and related databases. I will flag confidence levels where the full USPTO record could not be fully retrieved.

US 8,614,539 B2 — Prior Art & § 102 Anticipation Analysis

1. Patent Confirmation (USPTO)

Note on the numbering rule: the PTAB/IPR database and Google Patents confirm the identifier is 8614539 (no extra digits), which matches the application 13/273,215. I did not find any evidence that this number refers to the unrelated GB 8614539 A (a 1986 UK application for coordinate positioning apparatus, EP 0268659 family); that is a different, coincidental number.

2. Claim Landscape (Claims 1–19)

The granted patent has 19 claims (confirmed by the WO 2015/180630 A1 search report, which maps US 8,614,539 B2 against claims 1–19). The independent claim (claim 1) is directed to a light emitting device comprising:

• at least one solid-state light source (LED) operable to generate excitation light;
• a wavelength conversion component located remotely to the source, converting a portion of the excitation light to a different wavelength;
• the component containing at least one photoluminescence material and a light scattering material;
• the scattering material having an average particle size selected such that it scatters the excitation light relatively more than the light generated by the photoluminescence material (e.g., blue light scattered at least ~2× more than phosphor-generated green/red/yellow light; preferred TiO₂ average particle size <150 nm for blue excitation, <100 nm for UV excitation).

Dependent claims (inferred from the specification) cover: light transmissive substrate; a wavelength conversion layer (phosphor + binder) and a light diffusing layer (light diffractive material + binder) in direct contact; same binder in both layers; TiO₂ (or BaSO₄, MgO, SiO₂, Al₂O₃) as the diffractive material; weight loadings of 7%–35% (preferably 10%–20%); average particle sizes of 1–50 µm (preferably 10–20 µm) or nano-scale; screen-printing/slot-die deposition; phosphor quantity reduction (up to ~40%); OFF-state white appearance; angular color uniformity over ±60°; optional red LEDs for high CRI; and three-dimensional (dome-shaped) component geometries.

3. Prior Art References Cited on/Against US 8,614,539 B2

Caveat: The USPTO front-page "References Cited" list could not be fully retrieved within the search limit. The list below combines (a) references expressly cited in the specification, (b) references confirmed from the Unified Patents art database for the '539 patent, and (c) the family-related prior art surfaced in searches. I have prioritized the references most relevant to the claimed combination and have indicated where my confidence in the exact claim mapping is limited by the absence of the complete examiner's citation list and the full text of each reference.

A. Most Relevant — Remote Phosphor + Scattering/Diffusing Layers

A1. US 2004/0016908 A1 (Osram GmbH) — "Wavelength-converting Casting Composition and White Light-emitting Semiconductor Component"

• Priority/filing date: 1996-09-19 (family priority; publication ~2004)
• Description: Discloses a wavelength-converting casting composition for white LED semiconductor components, including phosphor particles and scattering/reflective particles dispersed in a transparent matrix, used on or spaced from the LED. This is one of the foundational Osram references on mixing scattering particles with wavelength-converting material to improve light output and color.
• Potential § 102 anticipation: The Osram casting composition teaches scattering particles in a wavelength-converting layer, but it does not clearly teach the selective particle-size relationship (scattering excitation light more than phosphor-emitted light) or a remote two-layer (diffusing layer in direct contact with conversion layer) structure of claim 1. Potentially anticipates claims directed to scattering particles mixed with phosphor in a single layer (if any claim is drawn to that narrower combination, e.g., claims covering scattering particles within the wavelength conversion layer as in FIG. 12/14 embodiments), but not the full claim 1 combination with the size-selective scattering limitation. Best characterized as § 102(b)/§ 103 (anticipation unlikely for claim 1; more relevant as obviousness art).

A2. US 2007/0240346 A1 (Intematix Corp.) — "Light Emitting Sign and Display Surface Therefor"

• Priority/filing date: 2006-03-07 (priority date per Unified Patents)
• Description: Intematix's own earlier remote-phosphor disclosure; light-emitting sign/display surfaces using photoluminescence wavelength conversion with a light source and a wavelength conversion component spaced from the source.
• Potential § 102 anticipation: Discloses remote wavelength conversion but does not disclose the size-selective light-scattering/diffusing layer (TiO₂ nanoparticles <150 nm scattering blue preferentially). Unlikely to anticipate claim 1; relevant to claims directed to remote-phosphor structural features (substrate + conversion layer) and as obviousness art.

A3. US 2006/0027786 A1 (Intematix Corp.)

• Priority/filing date: 2004-08-03 (per Unified Patents)
• Description: Intematix phosphor/light-emitting device disclosure (family related to the '539 patent's technology).
• Potential § 102 anticipation: Similar to A2 — remote/conversion component art without the selective scattering-particle-size limitation. Unlikely to anticipate claim 1.

A4. US 2005/0057917 A1 (Stanley Electric Co., Ltd.) — "Light Source and Vehicle Lamp"

• Priority/filing date: 2003-09-16
• Description: Light source/vehicle lamp using a phosphor layer and a light-diffusing member to improve color uniformity and appearance.
• Potential § 102 anticipation: Discloses a diffuser in combination with a phosphor, but not the specific particle-size-selective scattering relationship of claim 1. Potentially anticipates dependent claims directed to a diffusing layer in contact with a conversion layer if the diffuser is "in direct contact" — requires fact-specific review; more likely § 103.

A5. US 2007/0170840 A1 (LG Innotek Co., Ltd.) — "Phosphor and Light Emitting Device Using the Same"

• Priority/filing date: 2004-10-17
• Description: Phosphor compositions and LED devices using them.
• Potential § 102: Relevant to the phosphor-material claims; unlikely to anticipate the scattering-particle-size limitation of claim 1.

A6. JP 2002-133910 A (Toyoda Gosei Co., Ltd.) — "Phosphor Illumination Tube"

• Priority/filing date: 2000-10-23
• Description: Phosphor-based illumination tube — a remote-type phosphor arrangement with a tubular light-transmissive envelope.
• Potential § 102: Remote phosphor tube structure; does not teach the selective scattering particle size; relevant to remote-arrangement claims.

B. Foundational White-LED / Phosphor References (cited in the Background of the '539 patent)

B1. US 5,998,925 A (Shimizu et al., Nichia Corp.) — "Light Emitting Device Having a Nitride Compound Semiconductor and a Phosphor Containing a Garnet Fluorescent Material"

• Priority/filing date: 1996-07-28; granted 1999-12-07
• Description: The classic Nichia white LED: a GaN-based blue LED + YAG:Ce garnet phosphor that absorbs a portion of blue light and re-emits yellow, the combination appearing white. Cited expressly in the '539 specification as background.
• Potential § 102 anticipation: Discloses the blue LED + phosphor color-mixing principle but not a remote wavelength conversion component with a light diffusing layer or the selective scattering particle size. Does not anticipate claim 1; anticipates only the most generic prior-art propositions, which are not claimed in that form.

B2. US 6,255,670 B1 — "Phosphors for Light Generation from Light Emitting Semiconductors"

• Priority/filing date: 1998-02-05 (per Unified Patents)
• Description: Phosphor compositions for generating light from LED semiconductors.
• Potential § 102: Phosphor-material art; not directed to the diffusing-layer/scattering-size combination.

B3. US 6,340,824 B1 (Samsung Electronics) — "Semiconductor Light Emitting Device Including a Fluorescent Material"

• Priority/filing date: 1997-08-31
• Description: LED with fluorescent material, including arrangements for improved color.
• Potential § 102: Similar to B2; no selective-scattering diffusing layer.

B4. US 7,655,156 B2 — "Silicate-based Orange Phosphors" (Intematix family; priority 2005-08-02)

• Description: Silicate-based orange phosphors referenced in the '539 specification as suitable photoluminescence materials.
• Potential § 102: Only relevant to phosphor-composition dependent claims.

B5. US 7,575,697 B2 — "Silicate-based Green Phosphors" and US 7,601,276 B2 — "Two Phase Silicate-based Yellow Phosphors" (both cited in the '539 specification)

• Potential § 102: Phosphor-composition art only; not anticipation of the device claims.

B6. US 2006/0158090 A1 — "Novel Aluminate-based Green Phosphors" (cited in the '539 specification)

• Potential § 102: Phosphor-composition art only.

C. Other Confirmed Art in the Unified Patents Database for '539 (Lower Relevance)

These appear in the 178-item art record for the patent (which includes art beyond the examiner's formal citations, e.g., litigation/IPR art):

• US 6,500,301 B1 (Lumileds) — "Non-incandescent Lightbulb Package Using Light Emitting Diodes" (priority 1999-09-02): LED light-bulb packaging; relevant to the bulb/dome geometries of FIGS. 15–19, 24. No selective-scattering teaching.
• US 6,600,175 B1 (Wolfspeed/Cree) — "Solid State White Light Emitter and Display Using Same" (priority 1996-03-25): white light emitter with phosphor; foundational, not anticipation of claim 1.
• US 6,340,824 B1 (Samsung) — see B3.
• US 6,538,375 B1 (GE) — "OLED Fiber Light Source" (priority 2000-08-16): OLED fiber; low relevance.
• JP H01-179471 A (NIMS) — "Cubic Boron Nitride P-n Junction Light Emitting Device" (priority 1988-01-06): early nitride LED; low relevance.
• JP 2900928 B2 (Nichia) — phosphor LED patent (priority 1997-10-19): low-to-moderate relevance.
• US 3,932,881; 3,937,998; 3,972,717; 4,047,075; 4,081,764; 4,104,076; 4,143,394; 4,176,294; 4,176,299; 4,191,943; 4,211,955; 4,305,019; 4,315,192; 4,443,532; 4,559,470; 4,573,766; 4,618,555; 4,638,214; 4,667,036; 4,678,285; 4,727,003; 4,772,885; 4,845,223; 4,859,539; 4,915,478; 4,918,497; 4,946,621; 4,992,704; 5,077,161; 5,110,931; 5,126,214; 5,131,916; 5,143,433; 5,143,438; 5,166,761; 5,208,462 (1976–1993, various assignees: NEC, Philips, Ricoh, Xerox, Edmond/Cree, etc.) — these older references (electroluminescent devices, luminescent coatings, display/photoconductor art) appear in the citation record but are of low relevance to the claimed size-selective scattering diffusing layer; they would not anticipate claim 1.

4. § 102 Anticipation Assessment — Summary

Bottom line: Based on the available record, no single cited reference appears to disclose the complete claim 1 combination — specifically the remote wavelength conversion component in which the light scattering material's average particle size is selected so that it scatters excitation light (e.g., blue) relatively more than photoluminescence-generated light (e.g., TiO₂ nanoparticles of ~100–150 nm scattering blue at least ~2× more than green/red). The strongest § 102 candidates are the Osram casting-composition reference (for scattering-in-conversion-layer claims) and the Stanley vehicle-lamp reference (for diffuser-plus-phosphor claims), but each lacks at least one claim-1 element. The more likely validity attack on claim 1 is § 103 obviousness (e.g., Osram + Intematix remote-phosphor references), which is consistent with the instituted IPR2025-00698 proceeding.

5. Honest Limitations

1. Complete examiner citation list not fully retrieved — the USPTO/Google Patents front-page "References Cited" list could not be captured in full within the search limits. The analysis above covers the references I could confirm via the specification text, Unified Patents' art database, and family records. A complete claim-by-claim anticipation chart would require pulling the USPTO full-text "References Cited" section and the full text of each reference (many are non-English JP/older art).
2. Claims 1–19 full text — the granted claim set is not reproduced in the source text I was given (it ends at the Detailed Description). My claim mapping is inferred from the abstract, summary, and figures (e.g., the claim 1 language closely tracks the Abstract: "light scattering material has an average particle size that is selected such that the light scattering material will scatter excitation light ... relatively more than ... light generated by the photoluminescence material"). Confirm against the issued claims before relying on any specific claim mapping.
3. § 102 version — the patent was examined under pre-AIA law (filed 2011-10-13, priority 2010-10-05), so § 102(a)/(b)/(e)/(g) pre-AIA applies; the references above are analyzed under that framework, but I have not verified each reference's exact "prior art date" (publication vs. filing) for every item — several dates shown are priority dates from the Unified Patents database, not publication dates.

If you want, I can next pull the USPTO full-text References Cited page and the issued claims (1–19) to build a complete, claim-by-claim anticipation chart — that would require additional searches.

Obviousness Analysis of U.S. Patent No. 8,614,539 (Wavelength Conversion Component with Scattering Particles)

I. Executive Summary

U.S. Patent No. 8,614,539 ("the '539 patent") is currently the subject of an instituted inter partes review — IPR2025-00698, Savant Technologies LLC d/b/a GE Lighting, Elong International USA Inc., and Xiamen Longstar Lighting Co. Ltd. v. Feit Electric Company, Inc. (petition filed March 6, 2025; institution granted October 6, 2025). The petition challenges claims 1–11, 18–20, 23–25, and 28 under pre-AIA 35 U.S.C. § 103 using four grounds built on combinations of remote-phosphor LED prior art (Hussell, Basin, Van Woudenberg, Krummacher, Shimizu, and Stokes). The fact that the Board instituted trial is itself strong evidence that at least one combination presents a reasonable likelihood of prevailing on obviousness. Below I analyze the claims, the prior art, and the motivation-to-combine analysis, and I flag the genuine counterarguments (notably the McNulty "teaching away" history that led to allowance).

II. The Patent and Its Claims

Patent: US8614539B2, "Wavelength conversion component with scattering particles," Intematix Corporation (now Feit Electric Company, Inc.), filed October 13, 2011, claiming priority to October 5, 2010; granted December 24, 2013. Because the application was filed before March 16, 2013, pre-AIA § 103 governs.

Core invention (from the Abstract and Specification): A light emitting device with a solid-state source (blue LED) and a remote wavelength conversion component having (i) a wavelength conversion layer containing photoluminescence (phosphor) particles and (ii) a light diffusing layer containing light-scattering (diffractive) particles (e.g., TiO₂). The scattering particle size is selected so that the scattering material scatters the excitation (blue) light relatively more than — per the independent claims, "at least twice as much" as — light generated by the phosphor. Claimed/described attributes include: layers in direct contact; same transmissive binder (UV/thermally curable); TiO₂ weight loading of 7–35% (preferred 10–20%); average particle size 1–50 μm (preferred 10–20 μm) or nano-scale <150 nm for blue excitation; substrate of polymer or glass; and — added during prosecution — the component is configured so that a portion of excitation light comprising blue light ≥ 440 nm is emitted through the component to contribute to the final visible emission product.

Independent claims (1, 18, 28) were amended during prosecution to incorporate two key limitations: (a) "the light scattering material scatters the blue light at least twice as much as light generated by the at least one photoluminescent material," and (b) a portion of excitation light comprising blue light ≥ 440 nm is emitted through the wavelength conversion component to contribute to the final visible emission product. (Petition, IPR2025-00698, quoting file history, EX1104.)

III. Legal Framework

Under pre-AIA 35 U.S.C. § 103 and Graham v. John Deere, the inquiry is: (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill in the art; and (4) secondary considerations. Under KSR Int'l Co. v. Teleflex, a combination of known elements is obvious when a skilled artisan would have had a reason to combine them to solve a known problem with a reasonable expectation of success, including where the combination yields only predictable results or involves simple substitution/design choice.

Level of ordinary skill (POSITA): A person with a B.S. (or equivalent) in physics, materials science, electrical engineering, or optics, with roughly 2–5 years of experience in LED lighting, phosphor/wavelength-conversion materials, and optical design — consistent with the technical backgrounds described in the IPR expert declaration (EX1102, Declaration of William A. Doolittle, Ph.D.).

IV. Prior Art Landscape

A. Primary references relied upon in IPR2025-00698

B. References cited on the face of the '539 patent (USPTO/Google Patents "References Cited")

The most probative among the examiner-cited references for an obviousness challenge include:

• Chakraborty, US 2009/0050911 A1 — "Light emitting device packages using light scattering particles of different size"; and US 2008/0308825 A1 — "Encapsulant with scatterer to tailor spatial emission pattern and color uniformity in light emitting diodes." Both teach using scatterer particle size to control color uniformity — the same design lever as the '539 "at least twice" limitation.
• Hulse, US 7,686,478 B2 — "Bulb for light-emitting diode with color-converting insert" (remote phosphor bulb geometry).
• Baretz, US 7,943,945 B2 / US 7,615,795 B2 — solid-state white-light emitters with remote phosphor.
• McNulty, US 2002/0180351 A1 — the reference at the center of prosecution (discussed below).
• Reeh, US 2001/0000622 A1 — used with McNulty in an examiner § 103 rejection.
• Negley, US 2008/0130285 A1; Li, US 7,972,030 B2; Soules, US 7,479,662 B2; Bechtel, US 2009/0026908 A1 — additional remote-phosphor/scattering LED art.

V. Differences Between the Prior Art and the Claims

The principal claim elements and the closest prior art are:

1. Remote wavelength conversion component with two layers (phosphor layer + light-diffusing layer) in direct contact. — Disclosed in combination by Hussell (remote conversion tube) + Van Woudenberg (scattering layer) + Basin (remote phosphor scattering); Hulse (remote color-converting bulb insert) + Chakraborty (scattering layer for color uniformity) is an alternative route.
2. Scattering material particle size selected to scatter blue excitation light at least twice as much as phosphor-generated light. — Not literally disclosed in any single reference, but this is a predictable design choice derivable from (i) Chakraborty's teaching that scatterer particle size tunes scattering by wavelength, and (ii) the well-known Mie/Rayleigh scattering physics of TiO₂ documented in the DuPont and Thiele/French literature (petitioner exhibits 1112–1117), which shows 100–150 nm TiO₂ particles scatter blue (450–480 nm) more than twice as strongly as green (510–550 nm) or red (630–740 nm). FIG. 10 of the '539 patent itself plots exactly this known physics.
3. Portion of blue light ≥ 440 nm transmitted through the component to contribute to the final emission product. — Inherent in every blue-pump remote-phosphor white LED (Shimizu '925, US 6,069,440): some blue must pass unabsorbed to make white light. Hussell and Van Woudenberg likewise operate in this regime.
4. Off-state white appearance; angular color uniformity; reduced phosphor loading (up to 40%). — Explicitly the stated purposes of Van Woudenberg's scattering layer and Chakraborty's scatterer-tailored color uniformity; the phosphor-reduction benefit is the predictable consequence of photon recycling taught by Stokes' scattering particles.

VI. Obviousness Combinations and Motivation to Combine

Ground 1 — Hussell + Basin-2007 + Van Woudenberg (claims 1–11, 18–20, 23–25, 28)

• Hussell supplies the base device: an LED-based, incandescent-replacement lamp with a remote wavelength-conversion structure (the "wavelength conversion tube") — the claimed remote-component architecture.
• Basin-2007 supplies scattering particles in a remote-phosphor layer for color-consistency.
• Van Woudenberg supplies the light-scattering layer that produces a white off-state appearance, which is one of the '539 patent's express goals (Specification: the diffusing layer "improves the visual appearance of the device in an OFF state").

Motivation: All three references are in the same field (remote-phosphor, solid-state lighting) and address problems the '539 patent itself identifies: off-state yellow/orange appearance, angular color non-uniformity, and phosphor cost. A POSITA seeking to make Hussell's lamp appear white when off and uniform across viewing angles would combine Basin's scattering particles and Van Woudenberg's scattering layer with Hussell's remote conversion tube — an arrangement of known elements, each performing its known function, yielding a predictable result (KSR).

Ground 2 — Hussell + Krummacher + Stokes + Van Woudenberg (claims 18 and 28)

• Adds Krummacher's light-scattering translucent layer (tailoring spatial emission) and Stokes' scattering/reflective particles (boosting photon-phosphor interactions and thereby reducing phosphor loading).
• The claimed "at least twice" scattering ratio is satisfied by selecting TiO₂ particle size per the known scattering physics; Krummacher and Stokes provide the motivation to introduce scatterers, and the size selection is routine optimization.

Ground 3 — Krummacher + Shimizu + Stokes (independent claims directed to the conversion component)

• Shimizu (5,998,925 / 6,069,440) establishes the baseline blue-pump phosphor-converted white LED (including a portion of blue light passing through to form white light).
• Krummacher adds the light-scattering translucent layer; Stokes adds scattering particles to enhance conversion efficiency. A POSITA combining these obtains the claimed component with a reasonable expectation of success — the scattering layer is simply interposed between the source and the phosphor layer, as Van Woudenberg also teaches.

Ground 4 — Hussell + Van Woudenberg + Krummacher

• Overlap of Grounds 1 and 2: Hussell's remote conversion tube modified with Van Woudenberg's off-state-whitening scattering layer and Krummacher's light-scattering translucent layer. The petition's theory (per the patent owner response) is that these references "demonstrate why a person skilled in the art would be motivated to modify the 'wavelength conversion tube' in Hussell to create an off-state white appearance" (Pet. at 78).

Alternative examiner-cited-art combination (not in the IPR)

Chakraborty (US 2009/0050911; US 2008/0308825) + Hulse (US 7,686,478) + Shimizu (US 5,998,925): Chakraborty expressly teaches selecting scatterer particle size to tailor emission pattern and color uniformity in LED packages; Hulse teaches a remote phosphor bulb insert; Shimizu teaches the blue-pump white-light architecture. Combining them yields the claimed two-layer remote component with a size-selected scatterer — with the "at least twice" and "≥ 440 nm" limitations being design choices within the known Mie-scattering regime of TiO₂ (the '539 patent's own FIG. 10 confirms the ratio was known physics, not an invention).

VII. Why a POSITA Would Have Been Motivated to Combine

1. Same field, same problems. Every primary reference concerns solid-state/remote-phosphor lighting and addresses one or more of the exact problems the '539 patent claims to solve: off-state appearance (Van Woudenberg), angular color uniformity (Chakraborty, Krummacher), phosphor cost reduction (Stokes), and lamp form factor (Hussell, Hulse).
2. Known interchangeability of scattering layers. Remote-phosphor designers in 2010 routinely used TiO₂/white-ink scattering layers; substituting or adding a scattering layer to a remote conversion component was a standard design expedient (KSR's "design need or market pressure").
3. Predictable particle-size/wavelength relationship. The "at least twice" limitation is not a criticality or unexpected result — it follows directly from Mie-scattering theory and published TiO₂ scattering data (EX1112–1117), and is plotted in the patent's own FIG. 10. Choosing 100–150 nm TiO₂ particles for blue-pump systems is routine optimization of a known parameter.
4. No teaching away in the primary combination. Unlike McNulty (below), Van Woudenberg, Basin, Krummacher, and Stokes do not teach maximizing reflection to the exclusion of transmitted blue light; they operate in the transmissive, blue-leakage regime inherent to white remote-phosphor lamps.
5. The Board's institution decision. The PTAB's October 6, 2025 institution order (trial instituted as to the petitioned grounds) confirms that the prior art combinations raise a "reasonable likelihood" that at least one challenged claim is unpatentable under § 103.

VIII. Counterarguments (Why the Combination Arguments Are Contestable)

1. McNulty "teaching away" history. During prosecution, the Examiner rejected the claims over McNulty (US 2002/0180351) plus Reeh (US 2001/0000622). Applicant overcame the rejection by arguing that McNulty's goal is to maximize reflection of excitation radiation back into the phosphor — which would frustrate the claimed requirement that a portion of blue light ≥ 440 nm be emitted through the component to contribute to the final emission product. The Examiner agreed and allowed the claims (EX1104, 392–407). Feit will deploy the same "teaching away" argument against any reference (e.g., Stokes' reflective-particle design) whose stated purpose is maximum back-reflection.
2. The "at least twice" limitation. Feit will argue no reference quantifies the 2× scattering ratio, and that the prosecution history shows the limitation was added specifically to distinguish McNulty and was the basis of allowance.
3. Secondary considerations. Feit will point to long-felt need, commercial success of white-filament/off-state-white LED bulbs, industry praise, and copying (the co-pending district court litigation, Feit Electric Co. v. Savant Technologies, No. 1:24-cv-473 (N.D. Ohio)). The Patent Owner Response in IPR2025-00698 also attacks the Doolittle declaration as conclusory and hindsight-driven (e.g., arguing Krummacher's vertical-chip, large-area-lighting context is not combinable with Hussell's incandescent-replacement context).
4. Disparate application contexts. The PO Response contends that Hussell (incandescent replacement), Krummacher (large-area vertical chips), and Van Woudenberg (mobile-phone/downlight DIP/SMD) are "different applications of LEDs" with different packaging constraints, undermining a reasonable expectation of success.

IX. Assessment and Outlook

• Most vulnerable claims: The component claims (e.g., 18 and 28) and the method/apparatus claims that do not depend on the "emitted-through blue ≥ 440 nm" limitation, where the Hussell + Van Woudenberg + Basin/Krummacher/Stokes combinations are strongest.
• Most defensible limitation: The "portion of excitation light (blue ≥ 440 nm) is emitted through the component to contribute to the final visible emission product" requirement — because McNulty (the closest reflection-maximizing art) arguably teaches away, and the primary IPR references must be shown to operate in the transmissive regime.
• Procedural posture (as of April 26, 2026): IPR2025-00698 is instituted and pending (institution October 6, 2025); no final written decision has issued. A final decision on the merits is expected in 2026–2027, and any finding of unpatentability would be appealable to the Federal Circuit. The parallel district court case (N.D. Ohio 1:24-cv-473) is stayed or proceeding in parallel depending on the Board's timeline.

Bottom line: The most persuasive obviousness case is Hussell + Van Woudenberg + Basin-2007 (Ground 1), because Van Woudenberg expressly teaches the off-state white appearance and remote scattering-layer structure that the '539 claims, and Hussell supplies the remote conversion-tube geometry. The "at least twice" scattering ratio is the weakest differentiator as a matter of law because it is a predictable, known-physics design choice (TiO₂ Mie scattering), while the "emitted-through ≥ 440 nm blue" limitation is the strongest differentiator as a matter of fact because of the McNulty teaching-away history. The PTAB's decision to institute indicates that at least one ground has a reasonable likelihood of success; the outcome will hinge on whether the Board credits Feit's teaching-away and secondary-considerations arguments or the petitioner's showing that the combination is a routine, predictable aggregation of known remote-phosphor elements.

Note on sources: This analysis relies on the '539 patent text (Google Patents/FreePatentsOnline), the cited "References Cited" list, the prosecution history summarized in the IPR2025-00698 petition (PTACTS download, EX1104), the Patent Owner Response excerpts (PTACTS download), and the IPR docket (Unified Patents portal; gaeflexstaging docket page; ipverse.greyb.com). The exact text of the issued claims was not fully reproduced in the available search results; claim-element mapping above is based on the specification, abstract, and prosecution-history quotations, and should be verified against the certified claim set before litigation use.