Trichromatic beam splitter

Claim 1

An optics module for use with an apparatus for sorting articles by color, the sorting occurring through the analysis of video signals representative of light energy reflected from the articles being sorted as they pass through a viewed area, the video signals being generated by a plurality of vidicon tubes, comprising: a lens disposed at a predetermined distance form the viewed area, the lens being adapted to focus reflected light energy incident thereon onto a photosensitive target of the vidicon tubes, the vidicon tubes being disposed at a substantially equal focal length from the lens; and a beam splitter arrangement disposed optically adjacent to the lens along the axis of the incident light energy, the beam splitter arrangement including first, second, and third elements, the first element having first and second opposed surfaces and being disposed at a 45° angle with respect to the axis of the incident light energy, the second and third elements each respectively disposed perpendicularly to one of the opposed surfaces of the first element, the first, second, and third elements cooperating such that a first portion of the incident light energy passes therethrough along a first ray path axis which is coincident with the axis of the incident light energy and second and third portions of the incident light energy are reflected along respective second and third opposed ray path axes which are each perpendicular to the axis of incident light energy; the optics module further comprising: a housing; a support base mounted to the housing, the support base having a longitudinal axis extending parallel to the second and third ray path axes; first support plate mounted atop the support base and adjustably moveable in a direction parallel to the longitudinal axis of the support base; second support plate mounted atop the first support plate and adjustably moveable in a direction perpendicular to the longitudinal axis of the support base; a vidicon mounting plate extending upward from and perpendicular to the second support plate; and a yoke assembly for receiving each vidicon tube, the yoke assemblies being mounted on the vidicon mounting plate such that each yoke assembly is adjustably moveable in three mutually orthogonal directions with respect to the vidicon mounting plate.