Lighting device having light mixing optics and ring-shaped collimating structure

A lighting device comprising:

• a plurality of solid state lighting elements arranged in a ring-shaped geometry having a first central axis of symmetry;
• an optical element comprising a ring-shaped collimating structure configured to collimate light emitted by the plurality of solid state lighting elements, the ring-shaped collimating structure having a second central axis of symmetry, wherein the optical element is arranged in relation to the plurality of solid state lighting elements such that the first and second central axis of symmetry coincides;
• and
• light-mixing optics configured to mix light emitted by the plurality of solid state lighting elements, wherein the light-mixing optics comprises a microlens array comprising a plurality of lenslets arranged at least on an exit surface opposite to the ring-shaped collimating structure, said light-mixing optics is configured to apply a different degree of light-mixing in a tangential direction of the ring-shaped collimating structure than in a radial direction of the ring-shaped collimating structure, and
• wherein the optical element is arranged such that a focus of a segment of the optical element is on a nearest portion of the plurality of solid-state lighting elements arranged in a ring-shaped geometry;
• wherein the lenslets are elliptical and each has a smaller radius of curvature along the tangential direction of the ring-shaped collimating structure than in the radial direction of the ring-shaped collimating structure.