US 5,671,084 AGranted

Illumination system for a film scanner

AssigneeEastman Kodak Company

InventorAndrew F. Kurtz

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Abstract

A line light source illuminator for a film scanner of the type having a linear image sensor, a film gate through which an area of film to be scanned can be positioned, and an aperture at the film gate for defining the area of film to be scanned. The illuminator includes a light source which produces a light beam; an optical condenser between the lamp and the film gate to condense and shape the beam; and optics adapted to diffuse and direct the light beam so as to produce a uniform line of controlled diffuse illumination at the film gate. A spherical relay lens between the lamp and the optical condenser has a focal length nominally equal to a distance between the relay lens and the optical condenser to constrain the beam within the entrance pupil of the optical condenser. A spectral filter is between the lamp and the film gated to remove unwanted wavelengths of radiation from the light beam. The optical condenser comprises a spherical condensing lens adapted to alter the light beam so as to be slowly converging and to focus the beam down into a line of light. The optics comprises an integrating diffuser to transform the light so that the line of light at the film gate will have a substantially uniform intensity profile. The integrating diffuser is partitioned into plural regions with different diffusing properties in different regions of the integrating diffuser.

Claims5

Dependent claims

An illuminator system for a fill scanner of the type having a linear image sensor and fill gate means, through which an area of fill to be scanned can be positioned, for defining a linear film scan region, said illuminator system comprising:

a light source which produces a light beam;
optical means, located between said light source and the film gate means, for directing and shaping the light beam to intercept the film gate with a linear beam configuration generally corresponding to said linear film scan region;
illumination control means, located between said light source and said film gate means and including a plurality of discrete portions respectively having different light diffusing properties, for cooperatively redistributing the light beam so that the beam illumination at said film gate means has a predetermined radiance profile;
wherein
(i) said optical means for directing and shaping comprises a cylindrical lens means and a spherical lens means to respectively control and shape the beam and provide space for light regulating devices;
and
(ii) said illumination control means comprises first optical diffusing elements with differing light diffusing properties respectively in two planes perpendicular to the optical axis and second optical diffusing elements respectively with differing light diffusing properties at different spatial regions;
whereby said illumination control means transforms the light beam to be diffused in a controlled manner for scratch suppression and in predeterminedly controlled irradiance profile for film illumination uniformity.

5 more elements

Dependencies are inferred from the claim text.