Invalidity dossier
US 3241256
Method and means for integrally lighting an indicator with uniform brightness and with light conservation
Current assignee: Bendix Corp
Added 9/23/2026, 5:28:02 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 3,241,256 A
Title: Method and means for integrally lighting an indicator with uniform brightness and with light conservation
Patent number: US 3,241,256 A
Application number: US279723A
Assignee: Bendix Corp (original and current assignee as listed)
Inventors: Andre P. Viret; Fuhr Wolfgang
Filing/Priority date: 1963-05-13
Publication (grant) date: 1966-03-22
Legal status: Expired – Lifetime (anticipated expiration 1983-03-22, per the source's assumption-based listing)
Purpose: The patent addresses two problems with transilluminated indicator dials: considerable light loss and nonuniform brightness across the dial face. It aims to achieve light conservation and uniform brightness over the entire viewable area of an indicator dial, scale, or translucent tape, including the background.
Plain-language scope: A transparent light-conducting block (e.g., acrylic or methyl methacrylate plastic, with polished parallel upper and lower surfaces) carries lamps that inject light, which travels by internal reflection off the block's surfaces and edges. On the block's back surface are light-reflecting (diffuse-reflection) areas or "dots" in a dot pattern. Light striking a dot is diffusely reflected out through the front surface and an air gap onto a translucent dial or tape. To compensate for distance from the lamps, dots are larger, more densely distributed, or both, the farther they are from the light source. Light not reflected by a dot stays in the block via internal reflection and reflective edge coatings until it strikes a dot, conserving light. A light baffle above each lamp, or blackened lamp fronts/filters, prevents a bright spot directly above the lamp. Embodiments include a movable indicator tape (FIG. 1) and an indicator dial (FIGS. 2–8), including lamps at opposite ends of the block (FIGS. 7–8).
Source: https://patents.google.com/patent/US3241256/en
What the excerpt does not establish: It provides no claims text, no full description, and no drawings/figures. It does not establish claim scope, prosecution history, validity, ownership transfers, or the content of cited prior art (e.g., US 3,117,312 is mentioned only as drive-means context). The legal-status and assignee entries are the source's own assumption-based listings.
Generated 10/1/2026, 9:43:36 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
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.