Invalidity dossier
US 4282560
Added 9/23/2026, 1:34:01 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US Patent 4,282,560 — "Light Distributor"
Bibliographic data (from supplied text): Inventors George N. Kringel and Nicholas E. Sachuk; original and current assignee A C A Products Inc; prior art date 1979-01-15; filing date 1980-06-23; publication/grant date 1981-08-04; application US06/162,204; status listed as expired – lifetime, with anticipated expiration 1999-01-15. Classifications include G01G23/361 (indicating weight by electrical means using photoelectric cells), G01D11/28 (structurally-combined illuminating devices), and H03M1/26 (pattern-reading analog-to-digital conversion).
Purpose: The patent generally relates to light sensing and, more specifically, to illuminating light detectors. A described application is a shaft encoder in a bathroom scale, where a single low-voltage lamp illuminates an array of photocells through a coded disc, producing electrical outputs defining shaft rotation and thus a person's weight. The stated object is a cost-effective, convenient light distributor that spreads light from a conventional low-voltage bulb in a generally uniform and efficient manner across an edge of the guide.
Plain-language scope: A light-transparent guide intercepts light from a lamp supporting segment and directs it along a light-guiding direction to a longitudinal guide edge. The guide has opposite planar faces bounded by sides, at least one diverging from near the lamp supporting segment along a curve (e.g., parabolic or elliptic) selected so light from a source region reflects generally uniformly across the longitudinal guide edge. The lamp supporting segment seats the lamp so its filament lies at a level between the planar faces, allowing some filament-location variation while retaining sufficiently uniform distribution to activate the array. The guide may be molded transparent plastic, with a polished beveled edge reflecting light downwardly, and may be attached by heat-deformed protrusions.
Not established by this excerpt: The full claim language and claim count; FIG. 1–6 details and reference-numeral interpretations beyond the described portions; the complete specification text and any omitted passages; the co-pending Pfeiffer application's number or status; and any information about litigation, ownership transfers, validity, or prior art beyond the classifications and prior-art date shown.
Source: https://patents.google.com/patent/[US4282560](/patent/US4282560)/en
Generated 10/1/2026, 9:53:02 PM
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Litigation summary
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Proceedings on file (0)
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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
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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.