Box-shaped light fixture with diffuser lens having a plurality of diffractive ribs

A solid-state canopy light fixture comprising:

• a box-shaped housing including a base panel, and a plurality of side panels extending from the base panel and arranged to peripherally define an interior cavity and a top opening;
• a diffuser lens configured to cover the top opening of the housing, the diffuser lens comprising a plurality of concentric, diffractive ribs projecting outwardly from an inner lens surface, each of the diffractive ribs having a predetermined rib width, with at least one of the diffractive ribs having a rib width smaller than a rib width of an immediately adjacent diffractive rib, such that the at least one of the diffractive ribs diffracts transmitted light at a beam angle distinct from a beam angle of light transmitted by the immediately adjacent diffractive rib;
• a circuit board positioned within the interior cavity near the diffuser lens and carrying multiple discrete groups of solid-state lighting elements, with each group aligned with a corresponding diffractive rib;
• a reflective member formed on the circuit board and arranged to surround the solid-state lighting elements so as to direct light toward the diffuser lens;
• and
• an electronic control module electrically connected to the circuit board and configured to independently activate each group of solid-state lighting elements to adjust both light beam angles and correlated color temperatures.