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US 5,526,121 AGranted
Variable filter spectrophotometers
AssigneeEastman Kodak Company
InventorsJames R. Sandifer, David S. Uerz
Life of this patent
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AssigneeEastman Kodak Company
InventorsJames R. Sandifer, David S. Uerz
Estimating the term…
A variable filter spectrophotometer, for use with sample and reference; has a main member, a filter unit, a drive, a detector, a light distribution system, and a clamping circuit. The main member defines first and second beam paths, which are intersected by the filter unit. The filter unit has filtering and opaque portions. The filter unit is continuously movable relative to the beam paths in a repeating cycle from a first filtering relation in which the filtering portion is interposed in the first beam path and the opaque portion completely blocks the second beam path, to a first dark relation in which both beam paths are blocked, to a second filtering relation in which the filtering portion is interposed in the second beam path and the first beam path is completely blocked, and to a second dark relation in which both beam paths are completely blocked. The filtering portion is variably transmissive along a direction of movement of the filter unit. The drive continuously moves the filter unit relative to the beam paths. The detector produces a signal responsive to light received. The light distribution system directs light separately to and from the sample and reference, to and from the beam paths, and to the detector. The clamping circuit clamps the signal produced by the detector during the filtering relations to the signal produced by the detector during the dark relations.
A variable filter spectrophotometer for use with a sample and a reference, comprising:
A variable filter spectrophotometer comprising a main member having a pair of beam paths and an axis, said beam paths being disposed in uniform relation to said axis, said beam paths each having a periphery, a filter unit interposed in said beam paths, said filter unit being coaxial with said main member, said filter unit having filtering, blocking, and dark portions, said filter unit being continuously movable relative to said axis to move said filter unit portions through said beam paths, said filtering portion being variably transmissive to selected wavelengths of light along a direction of said movement of said filter unit, said blocking and dark portions being at least substantially opaque to said light transmittable by said filtering portion, said filtering portion having a maximum dimension in a direction of movement of said filter unit less than the minimum separation of said beam path peripheries, said blocking portion completely blocking one said beam paths continuously during the movement of said filtering portion through the other said beam path, said dark portion simultaneously interposable in both said beam paths.
Dependencies are inferred from the claim text.