Invalidity dossier
US 6882480
Optical device, optical unit and projector
Current assignee: Seiko Epson Corp
Added 9/23/2026, 6:03:33 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 6,882,480 B2
Title: Optical device, optical unit and projector
Patent number: US6882480B2
Application number: US10/632,836
Inventor: Yoshiyuki Yanagisawa
Assignee: Seiko Epson Corp (original and current assignee, per the listing; Google notes listed assignees may be inaccurate)
Priority date: 2002-08-08 (as listed; the source notes priority/filing dates are assumptions, not legal conclusions)
Filing date: 2003-08-04
Grant/publication date: 2005-04-19
Earlier publication: US20040046940A1 (2004-03-11)
Legal status (as listed): Expired – Fee Related; anticipated expiration 2023-08-04
Purpose and plain-language scope
The invention concerns an optical device that integrates an optical modulator for modulating color light according to image information with a color combining optical device that combines the modulated color light. It also covers an optical unit incorporating that optical device and a projector incorporating that optical unit. The background describes so-called three-plate projectors: light from a light source is separated into red, green and blue, modulated by three liquid crystal panels per color, combined by a cross dichroic prism, and projected enlarged through a projection lens.
The excerpt describes mechanical mounting and cooling context: liquid crystal panels may be attached to the light-incident side of the cross dichroic prism via pins inserted into holes at the four corners of a holding frame, or a wedge-shaped spacer may be interposed between the holding frame and the prism, as in Japanese Patent Laid-Open Publication No. Hei 10-10994. A polarization plate for aligning polarization direction is ordinarily attached and fixed on the light-incident side of the prism. The liquid crystal panel and polarization plate heat up under light-source irradiation and are forcibly cooled via a gap formed between them by the pin or spacer, through which cooling air passes.
Source: https://patents.google.com/patent/US6882480/en
What the excerpt does not establish
The supplied text is an excerpt; it does not provide the full claims, the complete written description, drawing contents, or the full list of cited prior art. It does not establish claim scope in detail, the specific cooling structures claimed, examination history, or the accuracy of the listed legal status or assignee.
Generated 10/1/2026, 9:43:02 PM
Cases on file (0)
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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.