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US4459647A Expired / Lapsed US ⏱️ 0.0 years remaining

Shadow-free lamp assembly

Assignee: Sankin Industry Co Ltd
•
Filing: 1983-01-26
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Granted: 1984-07-10
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Expires: 2003-01-26
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Abstract

Abstract A shadow-free lamp assembly comprises a plurality of plane mirror segments disposed on a basic paraboloidal reflecting surface, and a linear light source. Each of the plane mirror segments has a length of the short span of the paraboloidal reflecting surface as its long side and is continuously disposed next to each other along the long span of the paraboloidal reflecting surface and the light source is disposed in reflecting direction forward from the focus of the paraboloidal reflecting surface, whereby all mirror segments reflect light from the light source to produce irradiation patterns illuminating the single illumination area. Because of the overlapped illumination by the plurality of the mirror segments, shadow is not produced on the illumination area when reflected light is partially intercepted.

Inventors

  • 👤 Osamu Yamauchi
  • 👤 Kazuomi Hoashi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 22:57
CPC Classifications
F; F21; F21V; F21V7/00; F21V7/04; F21V7/09; F21S; F21S8/00; F21S8/08; F21V7/048; F21V21/00; F21V21/02; F21V21/04; F21W; F21W2131/00; F21W2131/20; F21W2131/202; Y; Y10; Y10S; Y10S362/00; Y10S362/804

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 132 words
A shadow free lamp assembly comprising a light source disposed forward in the reflecting direction from the focus of a basic paraboloidal reflecting surface, said paraboloidal reflecting surface having a longitudinal length and a transverse width, a plurality of mirror segments each having a longitudinal length and a transverse width, said plurality of mirror segments being disposed continuously in lengthwise side-by-side relationship to each other along the longitudinal length of said basic paraboloidal reflecting surface, each of said mirror segments having a straight transverse section and a parabolic longitudinal section, the longitudinal length of each mirror segment being generally equal to the transverse width of said basic paraboloidal reflecting surface, and said mirror segments being arranged such that light reflected from each of said mirror segments overlappingly irradiates the same illuminated area.
Claim 2
Dependent Claim 132 words
A shadow free lamp assembly comprising a light source disposed forward in the reflecting direction from the focus of a basic paraboloidal reflecting surface, said paraboloidal reflecting surface having a longitudinal length and a transverse width, a plurality of mirror segments each having a longitudinal length and a transverse width, said plurality of mirror segments being disposed continuously in lengthwise side-by-side relationship to each other along the longitudinal length of said basic paraboloidal reflecting surface, each of said mirror segments having a straight transverse section and a parabolic longitudinal section, the longitudinal length of each mirror segment being generally equal to the transverse width of said basic paraboloidal reflecting surface, and said mirror segments being arranged such that light reflected from each of said mirror segments overlappingly irradiates the same illuminated area.
Claim 3
Dependent Claim 34 words
A shadow free lamp assembly as defined in claim 1 wherein the transverse width of said mirror segments are determined so that reflecting light from said mirror segments overlappingly irradiate the same illumination area.
Claim 4
Dependent Claim 22 words
A shadow free lamp assembly as defined in claim 1 or claim 2 wherein said light source is a linear light source.

References Cited (Backward Citations)

US3666939A Cited
US4149227A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-07-10 1988-01-09 1988-07-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-07-10 1992-01-09 1992-07-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-07-10 1996-01-09 1996-07-10 $7700.00 Window Closed / Lapsed

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