Invalidity dossier
US 3752974
Uniform illumination with edge lighting
Current assignee: COASTAL DYNAMICS INCORPORATED A CORP OF OREG
Added 9/23/2026, 5:56:55 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 3752974 A
Title: Uniform illumination with edge lighting
Patent number: US 3752974 A (application US00207218A; also referenced as US3752974D A / US3752974DA)
Inventors: M. Baker; L. Myers
Assignee: Coastal Dynamics Corp (original assignee). The record also lists a current assignee, "COASTAL DYNAMICS INCORPORATED A CORP OF OREG," and shows reassignments to Allied Healthcare Products, Inc. (1981) and to Coastal Dynamics, Incorporated, a Corp. of Oregon (1982). Legal status is listed as "Expired – Lifetime."
Key dates: Prior art date and filing date: 1971-12-13. Publication/grant date: 1973-08-14. Anticipated expiration: 1990-08-14.
Purpose: The patent addresses lighting technique, specifically an improved system for providing substantially uniform illumination from edge-lighted optical media. Edge-lit panels minimize depth while illuminating a relatively large flat surface, but the excerpt states the resulting illumination "is still not uniform; that is, it tends to fall off with increasing distance from the light source measured in a plane parallel to the plane of the panel or optical medium itself." The stated primary object is to improve emission of substantially uniform light from a large surface using edge lighting while keeping wasted light to an absolute minimum.
Plain-language scope: Per the excerpt, the improvement involves diffusing one surface portion that normally provides internal reflection, so that at least some light rays striking the diffused surface are reflected through the opposite surface while others are refracted out through that same surface. A stated important feature is a "cleared area" about the light source, free of coating, with a radius preferably three to four times the thickness of the optical medium; beyond the cleared area the resulting light emission from the medium's surface is substantially uniform. The excerpt mentions 12 claims and 9 drawing figures.
Source: https://patents.google.com/patent/US3752974/en
What the excerpt does not establish: It does not provide the full claim language, complete description, or drawing contents; nor does it set out the precise coating materials, fabrication steps, or the full definition of "cleared area." It does not establish enforceability, validity, or the accuracy of the listed assignees or legal status.
Generated 10/1/2026, 9:43:09 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.