Invalidity dossier
US 4767172
Added 9/23/2026, 12:30:31 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US4767172A
Title: "Collector for an LED array"
Patent number / application: US4767172A (application US07/709,973)
Assignee: Xerox Corp (original and current assignee per the source listing)
Key dates: Priority date 1983-01-28; filing date 1985-03-11; publication/grant date 1988-08-30; anticipated expiration 2005-08-30. Legal status listed as "Expired – Lifetime."
Inventors: Virginia R. Nichols; Fred F. Hubble, III; James P. Martin
Purpose: The invention relates to a light collector for an LED array, particularly for use in an electrophotographic machine for patch generation on a photoreceptor surface and for pitch and edge erasure on that surface. The stated objects are to provide a new and improved light collector for an LED array and to provide such a collector for discharging selected portions of a photoconductive surface. The source identifies difficulties in prior art: loss of edge light not captured by light pipes, imperfect or uncollimated light entering a wave guide (causing uncontrolled light output and discharging of image portions), and the complexity and expense of mounting and packaging a large array of discrete LEDs.
Plain-language scope: Each LED sits centered in a hemispherical cavity in the collector array so radiation from the LED enters the collector essentially unrefracted. The collector array provides a convex lens portion and a parabolic reflecting surface portion. Light leaving the LED substantially perpendicular to its supporting substrate goes to the convex lens and is collimated; light exiting substantially parallel to the substrate strikes the parabolic reflecting surface at greater than the critical angle and is also collimated. The two concentric collimated beams are combined and applied to the photoreceptor surface via a light pipe or optical wave guide secured to the collector. Figures described include a prior-art LED light-capture configuration (FIG. 1), a collector profile (FIG. 2), the LED array with segmented light pipes (FIG. 3), and a sectional view of LED, collector, and light pipe (FIG. 4).
Not established by this excerpt: The full claims, detailed description, and drawing content are omitted (the source is excerpted). Consequently, claim scope, claim count, embodiments, and any specific materials or dimensions cannot be confirmed here. No litigation, ownership-transfer, validity, or prior-art analysis is presented.
Source: https://patents.google.com/patent/[US4767172](/patent/US4767172)/en
Generated 10/1/2026, 9:53:35 PM
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Litigation summary
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Proceedings on file (0)
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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
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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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