Invalidity dossier
US 4828888
Liquid crystalline polymer composites
Current assignee: Celanese Corp
Added 9/21/2026, 9:30:35 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US4828888A — "Liquid crystalline polymer composites"
Bibliographic data (as supplied)
- Patent number: US4828888A
- Title: Liquid crystalline polymer composites
- Application number: US07/015,758
- Inventors: Alan Buckley; Tessie M. Che; Thomas M. Leslie; James B. Stamatoff; Dagobert E. Stuetz; Donald R. Ulrich (listed as "Doanld R. Ulrich")
- Original assignee: Hoechst Celanese Corp
- Current assignee (per listing, which disclaims accuracy): Celanese Corp; Hoechst Celanese Chemical Co; Corning Inc; CNA Holdings LLC
- Priority/filing date: 1987-04-10; publication/grant: 1989-05-09; status: Expired – Lifetime (anticipated expiration 2007-04-10)
- Related filings listed: EP0286060A1; JPS63262617A; US4933111A; US4937013A
- Source: https://patents.google.com/patent/[US4828888](/patent/US4828888)/en
Purpose and plain-language scope (grounded in the supplied text)
The disclosure concerns composites combining a liquid crystalline polymer with a microporous structure. The prior-art keyword mapping associates the claims, abstract and description with: liquid crystal polymer; composite material; optical effect; inorganic oxide; oxide glass; sol-gel method; glass; porous material; and silicon dioxide (silica). Further indexed claim/description terms include aryl, azomethino, amide, azoxy, biphenylene, carbonyl, naphthylene, oxy, phenylene, spacer, sulfamoxole and thio groups; and, in the description, porous glass, smectic and nematic liquid crystals, electric fields, gels, leaching, solvents and acids (including hydrochloric and sulfuric acid), plus metals such as lithium, magnesium, aluminium, iron, nickel, tin, titanium and antimony.
In plain terms, the text indicates a composite in which a liquid crystalline polymer occupies or interacts with a porous (notably porous glass/oxide) matrix, with the porous glass preparable by leaching and the oxide by a sol-gel route, and with optical effects and electric-field response among the described properties.
What the excerpt does not establish
The supplied text is an excerpt: it omits the claims, abstract, full description, examples and drawings. It therefore does not establish the exact claim scope, claim count, claim language, specific composite compositions, process conditions, measured properties, or the identity/content of cited prior art. The listings of assignees, legal status, and priority/expiration dates are expressly stated by the source as assumptions, not legal conclusions; no verification of those entries is possible from this excerpt. No litigation, ownership-transfer, validity, or prior-art analysis is undertaken here, per scope.
Generated 10/1/2026, 10:02:19 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 4828888. 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.