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US 5,333,034 AGranted
System for selectively controlling the spectral make-up of visible light from a source thereof
AssigneeBremson Data Systems, Inc.
InventorsXue M. Gu, David B. Johnson, Michael S. Haines, Louis P. Armstrong
Life of this patent
Estimating the term…
Abstract
A preferred photographic printer (10) includes light filters (52, 54, 56) which can be shifted to selected positions for filtering respective spectral components from selected portions of a light beam (100) in order to vary the spectral make-up of the light beam, and further includes a preferred metal halide lamp (48) which produces a spectral output with substantial portions in the visible band.
Claims20
A photographic printing apparatus comprising:
- a light source operable for emitting a beam of visible light;
- a means for directing said light beam along a light path for interacting with a medium carrying an image and for subsequent impingement on an image sensitive medium for producing a representation of said image;
- at least one light filter including a single substrate having filter material operable for filtering a component of the visible spectrum from said beam when placed in the path thereof;
- means for positioning and maintaining said light filter in a selected one of a plurality filtering positions relative to said beam path for filtering said spectral component from a portion of said beam without filtering said component from the remaining portion thereof for achieving a desired intensity of said component in said beam,
- said filter material including a pair of spaced filter material sections with an open area therebetween, said sections cooperating to filter said component from said beam portion, said open area being devoid of filter material for passage of said remaining beam portion therethrough without filtering of said spectral component therefrom,
- said open area presenting an arcuate configuration extending along an arc adjacent the periphery of said light filter,
- said open area further presenting a width between said sections and presenting opposed ends with said width gradually narrowing from one of said ends toward the other said ends,
- said positioning means including means for selectively shifting said filter and thereby said open area relative to said beam to a selected one of a plurality of filtering positions for achieving a selected intensity of said spectral component the shape of said open area being defined so that said intensity of spectral component in the spectral beam varies substantially linearly with said filtering positions.
5 more elements
A photographic printing apparatus comprising:
- a light source operable for emitting a beam of visible light, said light source including an enveloped for containing a gas therein, a pair of electrodes within said envelope, and a gas contained within said envelope and responsive to electrical stimulation by said electrodes for emitting said light beam;
- means for directing said light beam along a light path for passage through a film negative and for subsequent impingement on photographic paper having photographic dyes thereon presenting respective spectral intensity peaks substantially corresponding to said sensitivity peaks;
- three disk-shaped, light filters respectively including cyan, magenta and yellow filter materials operable for filtering a respective spectral component from said beam, each of said filters being rotatable to a selected one of a plurality of filtering positions relative to said beam path for filtering said respective spectral component from a portion of said beam without filtering said component from the remaining portion of said beam;
- means operably coupled with said filters including a pair of spaced filter material sections with an open area therebetween, said sections cooperating to filter said component from said beam portion, said open area being devoid of filter material for passage of said remaining beam portion therethrough without filtering of said spectral component therefrom,
- each of said open areas presenting an arcuate configuration extending along an arc adjacent the periphery of said light filter,
- each of said open areas further presenting opposed ends and with the width thereof between said material sections narrowing gradually from one of said ends toward the other thereof for thereby presenting a corresponding filtering gradient said open areas being configured so that said filtering gradient is substantially linear.
3 more elements
Dependencies are inferred from the claim text.