Patent ID: 8797663

Claim:
A filter comprising: a plurality of lenses, each of the plurality of lenses configured to pivot about an associated pivot axis of a plurality of radially extending, substantially coplanar pivot axes extending from a common origin; a central lamp shield adapted to engage an electrode of an illumination source and supporting inner ends of each of the plurality of lenses, whereby the filter is centered relative to the electrode of the illumination source; an outer support having an inner peripheral support ring and an outer peripheral support ring, the outer peripheral support ring fixed relative to the central lamp shield and receiving outer ends of each of the plurality of lenses for pivoting about the pivot axes, and the inner peripheral support ring connected to the outer ends of each of the plurality of lenses so that rotation of the inner peripheral support ring relative to the outer peripheral support ring causes the lenses to pivot about the pivot axes; wherein, when pivoted to a closed position, the lenses pivot about the pivot axes to form a substantially planar ring-shaped composite lens substantially orthogonal to a direction of emittance of radiation from the illumination source; and wherein, when pivoted to an opened position, the lenses pivot about the pivot axes to be substantially co-planar with the direction of emittance of radiation from the illumination source; the lenses each having a relatively narrow, arcuate radially inner end and increasing in width radially outward to terminate in a relatively wide, arcuate outer end, and each of the pivot axes extends from the radially inner end to the outer end of a respective one of the lenses at a location offset from a center of the lens.