Invalidity dossier
US 6902310
Added 9/23/2026, 7:24:38 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US6902310B2
Title: Illumination system and projection display device employing the same
Patent number: US6902310B2 (application US10/353,948; pre-grant publication US20030147255A1)
Inventor: Yong-Seok Im
Assignee: Samsung Electronics Co., Ltd. (original assignee; assignment recorded 2003-01-30)
Key dates: Priority date 2002-02-01; filing date 2003-01-30; publication date 2005-06-07; adjusted expiration 2023-08-06. Status listed as "Expired – Fee Related" (Google notes legal status is an assumption, not a legal conclusion).
Purpose: The patent addresses drawbacks of conventional projection display light sources (xenon, metal-halide, or UHP lamps): high heat (about 500°C) requiring cooling fans, which cause noise and discharge hot air; emission of ultraviolet and infrared rays harmful to users and requiring filters; a broad spectrum producing a narrow color gamut and degraded color purity; and short average lamp life. The stated aim is a compact illumination system using a light source such as an array of light emitting diodes (LEDs) or laser diodes (LDs) having a longer life span, for use in a projection display device.
Plain-language scope: As described in the excerpt, the illumination system includes: a light source; a collimating lens array that makes emitted light parallel; an optical path conversion unit that reflects the parallel light back toward the light source to initially converge it; and a secondary focusing lens on the light source side that converges the reflected light onto a predetermined position. The optical path conversion unit may be a Fresnel lens with a mirror, an initial focusing lens with a mirror, a convex surface with a reflective back coating, a Fresnel lens with a reflective back coating, a holographic optical element, or a spherical concave mirror; gaps are variable. Optional features include an optical fiber to lead the converged light. The light source may be LEDs or LDs, may have an array structure with multiple emitters of different wavelengths, and the collimating lens array may use cylindrical convex lenses, an aspherical fly-eye system, or cylindrical-plus-spherical combinations. Figure 2 depicts a projection display device according to one embodiment.
Not established by this excerpt: The full claim set and their exact wording and dependencies; the complete detailed description, embodiments, and drawings; prosecution history; and any prior-art references. Figure 1's conventional device describes a lamp-based system with dichroic mirrors, mirrors, LCD panels, a dichroic prism, and a projection lens.
Source: https://patents.google.com/patent/[US6902310](/patent/US6902310)/en
Generated 10/1/2026, 9:42:07 PM
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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.