Beam splitter/combiner with path length compensator

Claim 1

A color imaging assembly for forming spatially separated, color component images of an object on a unitary image plane, comprising: (a) imaging means receiving a polychromatic imaging light beam from said object for imaging said object on said unitary image plane; (b) unitary beam splitter means having a plurality of parallel color component beam reflecting layers disposed obliquely in the path of said polychromatic, imaging light beam for splitting said polychromatic light beam into a plurality of parallel, spatially and spectrally separated, color component beams having optical axes positioned perpendicular to said unitary image plane; and (c) path length compensator means disposed between said beam splitter means and said unitary image plane for transmitting at least one of said spatially and spectrally separated color component beams therethrough for refractively compensating for differences in optical path lengths of said plurality of color component beams whereby each of said color component beams provides a focused color component image of said object on said unitary image plane, wherein said path length compensator means comprises: first transparent medium means having a first optical density and having a first end portion comprising a plurality of planar, parallel surface portions which each intersect a different color component beam at a different path length distance from said unitary imaging plane, wherein said first medium means comprises a first prism; and second transparent medium means having a second optical density different from said first optical density and having a first end portion comprising a plurality of planar parallel surface portions corresponding to said planar, parallel surface portions of said first transparent medium means and interfacing therewith, wherein said second medium means comprises a second prism.