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US4894683A Expired / Lapsed US ⏱️ 0.0 years remaining

Variable brightness light generators

Assignee: Eastman Kodak Co
•
Filing: 1988-12-05
•
Granted: 1990-01-16
•
Expires: 2008-12-05
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Abstract

Abstract There is disclosed a variable brightness light generator embodied in apparatus for exposing photographic film for test purposes. The generator includes a spherical mirror, a lamp at the center of the spherical form of the mirror and a modulator located between the lamp and the mirror for modulating the brightness of the image of the lamp created on the lamp by the mirror. The intensity of the light issuing from the lamp is sensed by a spectroradiometer which produces signals used in controlling the modulator whereby the intensity may be kept constant. The color temperature of the lamp is controlled under the influence of signals from the spectroradiometer. The exposing apparatus also includes a plurality of filters selectively insertable in the light path for modifying the intensity and color of the light incident on the film.

Inventors

  • 👤 Kevin P. McGuire
  • 👤 James D. McKay

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 05:02
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 45 words
A variable brightness light generator, including: a spherical mirror; a lamp located at the center of the spherical form of said mirror; and a modulator located between the lamp and the mirror for modulating the brightness of the image of the bulb on the bulb.
Claim 2
Dependent Claim 45 words
A variable brightness light generator, including: a spherical mirror; a lamp located at the center of the spherical form of said mirror; and a modulator located between the lamp and the mirror for modulating the brightness of the image of the bulb on the bulb.
Claim 3
Dependent Claim 19 words
A variable brightness light generator as claimed in claim 1, wherein: said modulator is of the variable aperture type.
Claim 4
Dependent Claim 25 words
A variable brightness light generator as claimed in claim 3, wherein the variable aperture modulator includes two shutters movable towards and away from one another.
Claim 5
Dependent Claim 42 words
A variable brightness light generator as claimed in claim 3, wherein: said two shutters are formed of the same material as the reflective surface of the mirror whereby light whether reflected by the mirror or the shutters has the same spectral composition.
Claim 6
Dependent Claim 35 words
A variable brightness light generator as claimed in claim 4, wherein: the material of the shutters and of the reflective surface of the mirror is aluminum and the surfaces of the shutters are diffusely reflective.
Claim 7
Dependent Claim 62 words
A variable brightness light generator as claimed in claim 3, wherein: said modulator further includes a stepping motor for moving one blade in its plane, and a lever acting between the two blades to transmit motion from said one blade to the other blade but with the motion of said other blade being opposite in direction to that of said one blade.
Claim 8
Dependent Claim 34 words
A variable brightness light generator as claimed in any one of claims 1 to 6, wherein: said light bulb is of of the low voltage tungsten halogen type, whereby the filament may be small.

References Cited (Backward Citations)

US2686452A Cited
US3517201A Cited
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US4050813A Cited
US4194834A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-01-15 1993-07-17 1994-01-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-01-15 1997-07-17 1998-01-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-01-15 2001-07-17 2002-01-16 $7700.00 Window Closed / Lapsed

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