Invalidity dossier
US 5629980
Added 9/23/2026, 4:44:44 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 — US5629980A
Title: System for controlling the distribution and use of digital works
Patent number: US5629980A (application US08/344,042)
Assignee/owner of record in the excerpt: Original assignee Xerox Corp; current assignee listed as Contentguard Holdings Inc.
Inventors: Mark J. Stefik; Michalene M. Casey
Key dates (as listed): Priority date 1994-11-23; filing date 1994-11-23; publication/grant 1997-05-13; anticipated expiration 2014-11-23; status "Expired - Lifetime."
Purpose and plain-language scope (per the supplied text): The patent is titled and classified as a system for controlling the distribution and use of digital works. Its classifications place it in network security, digital rights management ("Protecting distributed programs or content, e.g. vending or licensing of copyrighted material; Digital rights management [DRM]"), data-network charging/metering/billing, digital cash payment, tariff aspects, and cryptographic entity authentication using certificates. The record also notes "Family has litigation" and identifies prior-art keywords: repository, digital, transaction, usage, work. No claims, abstract, or detailed description text appears in the excerpt.
Source: https://patents.google.com/patent/[US5629980](/patent/US5629980)/en (fetched 2026-09-23).
What the excerpt does not establish: The excerpt consists only of bibliographic, classification, family, and status metadata plus an images placeholder. It contains no claim language, no abstract or specification, and no drawing text. Accordingly, it does not establish the actual claimed scope, the specific mechanisms by which a repository controls distribution, transaction, or usage of a digital work, any certificate or digital-cash implementation details, or any legal conclusions. The noted legal status and priority dates are expressly assumptions, not conclusions. Statements about assignees are likewise described in the source as potentially inaccurate listings.
Per instructions, no research into litigation, ownership transfers, validity, or prior art was performed.
Generated 10/1/2026, 9:44:14 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 5629980. 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.