Invalidity dossier
US 5600462
Optical film and liquid crystal display device using the film
Current assignee: AUO Corp
Added 9/23/2026, 9:08:36 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 — US5600462A
Title: Optical film and liquid crystal display device using the film
Patent number: US5600462A | Application number: US08/121,657
Inventors: Masaru Suzuki, Fumihisa Hanzawa, Manabu Mogi
Original assignee: International Business Machines Corp (assignment recorded 1993-12-15). The source's "Current Assignee" field lists AUO Corp, with a 2005-12-21 reassignment from IBM to AU Optronics Corporation. Per instructions, no ownership analysis is offered beyond what the source states.
Key dates: Prior art date 1992-09-16; filing date 1993-09-14; publication/grant 1997-02-04; anticipated expiration 2014-02-04. Legal status: Ceased.
Purpose (from the supplied text): The patent concerns an optical film and a liquid crystal display device using that film. The recurring prior-art keywords are "crystal display," "liquid crystal," "light," "prisms," and "display panel," indicating the film is used to direct light toward a liquid crystal display panel via prism structures. Classification data supports this reading: the document is classified for light guides, prism arrays (G02B5/045), brightness-enhancement prismatic sheets or layers (G02B6/0053), edge-illuminating devices (G02F1/133615), and diffusing elements with microprismatic or micropyramidal surface structure (G02B5/0231).
Plain-language scope (limited to the excerpt): The disclosure covers a transparent optical film having microprismatic surface structures, and a liquid crystal display device incorporating such a film—consistent with a brightness-enhancement film for a backlit LCD. The excerpt's keyword list also references "biological transmission," "transparent material," "matrix material," and a single mention of "crystal," though the excerpt does not show claim language defining these terms.
What the excerpt does not establish: The excerpt contains no claim text, no abstract text, no description body, no named prior-art references, and no figures' content. It therefore cannot support statements about the specific claimed structure, layer thicknesses, prism angles, materials (e.g., polycarbonate, epoxy resin, PMMA appear only as keyword/substance listings without context), or the scope of any individual claim. The excerpt likewise does not establish the reasons for cessation, the family members, or the litigation referenced by the third-party link.
Source: https://patents.google.com/patent/[US5600462](/patent/US5600462)/en
Generated 10/1/2026, 9:40:57 PM
Cases on file (0)
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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.