Invalidity dossier
US 5375043
Lighting unit
Current assignee: Inoue Denki Co Inc
Added 9/23/2026, 9:11:39 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US5375043A — "Lighting Unit": Patent Overview
Bibliographic data (from supplied text): Title: "Lighting Unit." Patent number: US5375043A. Inventor: Makoto Tokunaga. Original and current assignee: Inoue Denki Co., Inc. Application number: US08/087,640. Filing date: 1993-07-06. Priority date: 1992-07-27. Publication/grant date: 1994-12-20. Legal status listed: "Expired - Fee Related." Source: https://patents.google.com/patent/[US5375043](/patent/US5375043)/en
Purpose. The patent addresses a known problem in indirect-type lighting units: conventional units that use a fluorescent lamp or tungsten halogen lamp on the side edges of a transparent light guide plate consume too much power for small, battery-powered products (for example, a pocket calculator, portable telephone set, or portable game machine) whose display surfaces use liquid crystal. Because of that power consumption, most such products did not employ these lighting units.
Plain-language scope. The supplied text describes a lighting unit of the indirect type comprising:
- a light guide plate made of a small-sized uncolored or colored transparent plate, with one side fashioned into an uneven surface or a reflective layer;
- a plurality of light emitting diodes (LEDs) as light sources supplying light to the light guide plate, the light being dispersed through the plate; and
- a control section that controls actions including blinking of the plurality of LEDs.
The background also notes that indirect-type units scatter light via the uneven surface or reflective layer to illuminate the transparent plate substantially uniformly, and that such units have generally trended toward more uniform lighting, larger lighting area, or increased illuminance.
What this excerpt does not establish. The excerpt is explicitly marked as partial ("consult the source for omitted text"). It provides no claim text, so the metes and bounds of the claimed invention cannot be stated here. It also does not establish the full description or embodiments, the complete list of referenced prior art, prosecution history, the accuracy of the listed legal status, or whether the classification entries reflect claim scope.
No litigation, ownership-transfer, validity, or prior-art analysis is offered, per instruction.
Generated 10/1/2026, 9:40:53 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.