Invalidity dossier
US 4258643
Illuminated indicator gauge with illuminated pointer
Current assignee: Nissan Motor Co Ltd
Added 9/23/2026, 3:26:39 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: US4258643A — Illuminated Indicator Gauge with Illuminated Pointer
Title: Illuminated indicator gauge with illuminated pointer (as listed on the source page).
Assignee/Inventor: Original assignee Nissan Motor Co Ltd. Inventors Masao Ishikawa, Kenji Nakamura, and Akio Ajimine.
Dates (per source page):
- Priority date: 1978-06-21
- Filing date: 1979-06-08 (application US06/046,643)
- Publication/grant: 1981-03-31
- Legal status: Expired – Lifetime; anticipated expiration noted 1999-06-08.
Purpose: The patent addresses illuminated indicator gauges (e.g., speedometers, tachometers for motor vehicles) having a pointer illuminated internally by light from lamps travelling through the dial board. The background states that in prior gauges light utilization was poor due to non-ideal light reflecting surfaces, producing weak pointer illumination. The stated objects are to use the light effectively and to enhance illumination of the pointer.
Plain-language scope: A light guiding plate is made integral with the dial board proper from a transparent material. Light enters the guiding plate and is reflected by a reflecting surface toward the region where the guiding plate and dial board proper connect, focusing light near an opening in the dial board through which the movement's spindle passes. The transparent dial board comprises a main rounded section and projecting light guiding sections, each with a recess receiving a lamp; a convex surface lets light travel parallel toward the opening. Slanted surfaces (about 45°) at the opening reflect light to a curved reflecting surface on the pointer hub, directing light up the pointer for internal illumination.
Embodiments: First (FIGS. 1–2) with laterally projecting rounded sections and convex surfaces; second (FIGS. 3–5) with bent rounded sections extending perpendicularly and flat 45° reflecting surfaces, enabling a compact dial board; third (FIG. 6) with recesses having cylindrical and flat surfaces and flat peripheral surfaces.
Not established by the excerpt: Full claims, complete description, drawings, and independent/dependent claim structure are omitted; the abstract and description are partial. No information is provided on litigation, ownership transfers, validity, or prior-art analysis, which are outside this overview.
Source: https://patents.google.com/patent/[US4258643](/patent/US4258643)/en
Generated 10/1/2026, 9:51:36 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 4258643. The free-form analysis below may also discuss cases beyond this list.
No cases on file mention this patent. Upload a CSV or add a case manually in Admin → Manage litigation cases.
Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
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.