Invalidity dossier
US 5381309
Backlit display with enhanced viewing properties
Current assignee: Honeywell Inc
Added 9/23/2026, 8:41:12 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 — US 5,381,309
Title: Backlit display with enhanced viewing properties
Patent number: US5381309A (application US08/130,084)
Inventor: Jerry L. Borchardt
Assignee: Honeywell Inc. (original assignee; assignment recorded 1993-09-30)
Key dates: Filed 1993-09-30; priority 1993-09-30; granted/publication 1995-01-10; anticipated expiration 2013-09-30. Legal status listed as "Expired – Lifetime." Related filings noted: AU78795/94A and PCT/US1994/010888 (WO1995009380A1), both with priority 1994-09-27.
Purpose (from the supplied text): The patent addresses a backlit display with enhanced viewing properties. The excerpt emphasizes illumination, an optical cavity, optical effects, enhancing effects, diffusion, liquid crystal substances, and transparent materials.
Plain-language scope (as the excerpt indicates): The disclosure concerns backlit display illumination technology built around an "optical cavity" bounded by walls, with light travel and diffusion managed to enhance viewing. It relates to liquid crystal displays and optical films, including polyester film. It is classified in optics and light-guide areas (G02B6/00–G02B6/0013, G02B6/0038, G02B6/0051, G02B6/0068) and in lighting-refractor areas (F21V5/00, F21V5/02). Classifications also cover edge-illuminating devices for liquid crystal cells (G02F1/133615), plural light sources (G02B6/0068), LEDs (F21S43/14, F21Y2115/10), and combinations of reflectors and refractors (F21S43/40). Prior-art keywords include cavity, optical, major wall, light, and optical cavity.
Source: https://patents.google.com/patent/US5381309/en (fetched 2026-09-23).
What the excerpt does not establish: The supplied text contains no claims, abstract, or description body. It therefore does not establish the actual claimed scope, claim limitations, specific embodiments, dimensions, materials, or the number and content of claims. It provides no prior-art documents or citations, so novelty and non-obviousness cannot be assessed. The classification and keyword lists are indexing annotations, not claim language. No information is supplied about litigation, licensing, ownership transfers, or validity. Dates and legal status are Google Patents' assumptions, expressly stated as non-legal conclusions.
Generated 10/1/2026, 9:41:15 PM
Cases on file (0)
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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
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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.