Invalidity dossier
US 5396350
Added 9/23/2026, 6:59:12 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,396,350 A
Title: "Backlighting apparatus employing an array of microprisms." The reference designates Karl W. Beeson, Scott M. Zimmerman, and Paul M. Ferm as inventors. Original assignee is AlliedSignal Inc.; the current assignee listed is Advanced Display Technologies of Texas LLC. Priority and filing date: 1993-11-05 (application US08/149,219). Publication/grant date: 1995-03-07. Status: Expired – Lifetime, with anticipated expiration 2013-11-05.
Purpose. The invention relates generally to flat panel electronic displays and, more particularly, to an apparatus for collimating light usable as a backlight providing relatively high light transmission for liquid crystal displays or the like. The text states it is directed to direct-view flat panel displays, specifically an LCD, having an improved backlight assembly giving an energy efficient and uniform light source, and also to any lighting application requiring a low profile, substantially collimated light source.
Plain-language scope (from the supplied text). A flat panel display comprises a modulating means (e.g., an LCD) spaced from a backlit assembly: a light source in close proximity to a light transmitting means, arranged so light rays travel through that means in a direction substantially parallel to the plane of the modulating means. A reflecting means, operatively disposed between and in close proximity to the light transmitting means and the modulating means, collimates the light rays. The light transmitting means may be a light pipe, light wedge, or slab waveguide; in described embodiments a slab waveguide transports light by total internal reflection, with an array of microprisms on one face. Each microprism has a light input surface adjacent the waveguide, a parallel distal output surface, and a tilted sidewall angled so rays escape the waveguide, reflect through the microprism via TIR, and emerge substantially collimated and perpendicular to the modulating means. Embodiments may use two light sources at oppositely disposed light-accepting surfaces.
Source: https://patents.google.com/patent/US5396350/en
What the excerpt does not establish. The provided text is explicitly excerpted and truncated (and the images are not rendered), so it does not set out the full specification, all claims, the complete drawing set, or the full list of cited prior art. Dates, status, and assignee entries are as listed by the source, which notes legal-status and assignee information are assumptions, not legal conclusions; no independent verification was performed.
Generated 10/1/2026, 9:42:23 PM
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Litigation summary
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Proceedings on file (0)
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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.