Invalidity dossier
US 6151169
Sheet type optical device and backlighting unit using the same
Current assignee: LG Display Co Ltd
Added 9/23/2026, 7:16:18 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 6,151,169 A
Title: Sheet type optical device and backlighting unit using the same
Inventor: Wook Sung Kim
Original Assignee: [LG Electronics Inc.](/litigations/by-plaintiff/LG%20Electronics%20Inc.) (later recorded as LG.Philips LCD Co., Ltd., then LG Display Co., Ltd.)
Application No.: US 09/205,879
Filing Date: 1998-12-04
Priority Date: 1998-05-20
Publication/Grant Date: 2000-11-21
Legal Status (as listed): Expired – Lifetime; anticipated expiration 2018-12-04
Purpose: The invention addresses problems in conventional sheet type optical devices, which require two prism sheets to emit light within a constant angular range. Such designs have a complicated structure, more fabrication steps, higher manufacturing cost, and a thickness that is difficult to reduce below a certain limit. The stated objects are to provide a sheet type optical device that stands obliquely progressing light perpendicular to the plane, and a backlighting unit with simplified structure, shortened manufacturing process, and reduced thickness.
Plain-language scope: The device is a transparent sheet of transmissive material with a plurality of parallel prisms formed on one surface. The prisms have a vertical (apex) angle of about 50° to 70°. Light received obliquely relative to the second surface — including within about 15° to 50° of the normal to that surface — is output almost perpendicularly from the first surface. The backlighting unit includes a light source, a light guide with a light incident surface and a light emitting surface, and a reflective plate; the description also covers a diffusion panel, prism sheets, and a protective film in the conventional arrangement the invention seeks to simplify.
Source: https://patents.google.com/patent/US6151169/en
What the excerpt does not establish: The supplied text is explicitly marked as an excerpt with omitted portions. It does not provide the full claims, the complete detailed description, drawing content, or the exact backlighting-unit claim language (which is cut off mid-sentence). Assignee, dates, and legal status are drawn from the source's bibliographic listings and are noted there as assumptions or non-legal conclusions. No litigation, ownership-transfer, validity, or prior-art analysis is offered here.
Generated 10/1/2026, 9:42:13 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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