Invalidity dossier
US 6565225
Bar-shaped light guide, beam lighting device using the bar-shaped light guide, and surface lighting device using the beam lighting device
Current assignee: Sanyo Electric Co Ltd
Added 9/23/2026, 5:52:02 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 6,565,225 B2
Title: Bar-shaped light guide, beam lighting device using the bar-shaped light guide, and surface lighting device using the beam lighting device
Assignee: Sanyo Electric Co., Ltd. Inventors: Koji Mabuchi, Youichiro Goto, Toru Nose, Nobuo Iwatsuki. Application: US 09/906,846, filed 2001-07-18. Priority date: 2000-07-19. Granted/published: 2003-05-20. Status (as listed): Expired – Fee Related, adjusted expiration 2021-10-02. Source: https://patents.google.com/patent/US6565225/en
Purpose. The patent addresses utilization efficiency of light entering a bar-shaped light guide from a point light source (e.g., an LED). In the described background arrangement, the guide is a right prism with a rectangular cross-section and uniform thickness, so the reflecting surface is parallel to the light's optical axis; much incident light never reaches the reflecting surface or the V-shaped grooves, reducing efficiency. Light emitted from the light-emitting surface also required a diffusing sheet and lens sheet for correction, raising cost and assembly steps.
Plain-language scope (per the excerpt). The claimed bar-shaped light guide comprises: a light incident surface receiving light from a point light source; a light emitting surface orthogonal to the incident surface, emitting the received light as beam light; and a pattern surface made up of a side of the incident surface and a side of the emitting surface, including a plurality of grooves formed thereon. The excerpt begins describing the grooves but is truncated at that point, so their full geometry and arrangement are not established here. The document also contemplates a beam lighting device using the guide and a surface lighting device using that beam lighting device. Classifications include G02B6/0038 (linear indentations or grooves extending over the full length or width of the light guide) and G02B6/0061 (varying density, size, shape or depth along the light guide to provide homogeneous light output intensity).
What the excerpt does not establish. It does not provide the complete claim text, the full description of groove pitch/depth, all drawing content, or the specific claims distinguishing the invention from the cited JP 2000-11723 A. It states no litigation, ownership-transfer, or validity conclusions.
Generated 10/1/2026, 9:43:14 PM
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Litigation summary
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Proceedings on file (0)
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PTAB challenges
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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
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Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.