Invalidity dossier
US 6936968
Retrofit light emitting diode tube
Current assignee: Mule Lighting Inc
Added 9/23/2026, 2:11:16 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 6936968 B2
Title: Retrofit light emitting diode tube
Patent number / application: US 6936968 B2; Application US09/998,274
Inventors: Robert Porter Cross, Robert Hartwell Cross, Jeffery Parker Cross (assignment recorded as "CROSS, JEFERY P., CROSS, ROBERT H., CROSS, ROBERT P." — the spelling differs between the two entries in the source)
Assignee: Mule Lighting, Inc. (original and current assignee)
Dates: Priority date 2001-11-30; filing date 2001-11-30; published as US20030102810A1 on 2003-06-05; granted 2005-08-30. Legal status listed as "Expired – Lifetime," adjusted expiration 2022-08-08. Google notes these statuses and dates are assumptions, not legal conclusions.
Purpose: The disclosure is directed to a solid-state lamp using light-emitting diodes (LEDs) designed as a replacement illumination source for fluorescent lamps, particularly in troffer-type fixtures. It notes disadvantages of fluorescent lamps, including hazardous ionizable material and fill gases, ballast failure and replacement, and energy costs.
Plain-language scope (per the supplied text): The retrofit LED light tube generally comprises an elongated cylindrical transparent envelope; a base cap at each end with first and second prongs adapted to electrically communicate with a fluorescent light socket; and at least one LED device in electrical communication with the base cap, with its positive terminal connected to the first prong and negative terminal to the second prong. In a further description, at least one serial string of LEDs connects to an AC source through a nondissipative voltage dropping element, with strings in parallel enclosed in the envelope. The disclosure also describes a troffer fixture with a housing and tube holder having sockets to receive the prongs, plus figures including ballast conversion circuitry and AC-to-DC conversion schematics. Classifications include F21K9/27 (retrofit sources for fluorescent tube substitution) and H05B45/3578 (emulating discharge-lamp characteristics).
What the excerpt does not establish: It does not provide the full claim text, complete description, or full figure descriptions; the text is expressly marked as an excerpt. It does not establish prosecution history, claim construction, enforceability, or the content of any prior-art reference. Litigation, ownership transfers, validity, and prior art were not examined.
Source: https://patents.google.com/patent/US6936968/en (fetched 2026-09-23).
Generated 10/1/2026, 9:52:28 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 6936968. The free-form analysis below may also discuss cases beyond this list.
No cases on file mention this patent. Upload a CSV or add a case manually in Admin → Manage litigation cases.
Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.