Invalidity dossier

US 8639935

Current assignee: Headwater Research LLC

Added 8/28/2026, 12:48:27 AM

At a glanceNo PTAB challenges6 lawsuits on fileasserted by Headwater Research LLC

Active provider: DeepSeek · deepseek-v4-flash

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Patent summary

Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.

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Cases on file (6)

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Specific litigation cases in our database that name US patent 8639935. The free-form analysis below may also discuss cases beyond this list.

Litigation summary

Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.

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Proceedings on file (0)

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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.

Current assignee: Headwater Research LLC

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.

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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.

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Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

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Obviousness

Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.

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Extensions

Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.

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Derivative works

Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.

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More patents asserted by Headwater Research LLC

This patent in court (6)

6 tracked lawsuits name US 8639935.