Troffer-style fixture

A lighting troffer, comprising:

• a pan structure comprising an inner reflective surface and defining a bottom edge;
• a body comprising a bottom edge and a back reflector on a bottom-side surface of said body, the body mounted inside said pan structure such that said inner reflective surface surrounds said body
• an elongated heat sink mounted proximate to said back reflector and running longitudinally along a central region of said back reflector, said heat sink offset from said back reflector in a vertical direction such that said heat sink is entirely below the bottom edge of said body in the vertical direction and is above the bottom edge of the pan in the vertical direction;
• a plurality of light emitting diodes (LEDs) on a mount surface of said heat sink that faces toward said back reflector;
• and
• lens plates on each side of said heat sink and mounted between said heat sink and said back reflector such that said back reflector, said heat sink, and said lens plates define an interior cavity.

A lighting unit, comprising:

• a back reflector defining a bottom edge, said back reflector comprising:
• a spine region that runs longitudinally down said back reflector;
• and
• a first side region on a side of said spine region;
• a heat sink mounted proximate to said back reflector, said heat sink comprising a top-side mount surface, wherein a region between said heat sink and said back reflector defines an interior cavity;
• and
• a plurality of light emitters on said mount surface and aimed to emit light toward said back reflector, said mount surface proximate to said spine region, said mount surface comprising a flat area facing said back reflector, said flat area configured such that said plurality of light emitters is substantially above said heat sink, and wherein a longitudinal center of said flat area is substantially in line with a longitudinal center of said spine region in a first direction;
• said mount surface offset from said back reflector such that said mount surface is entirely below said bottom edge of said back reflector in a second direction perpendicular to the first direction.

A light unit, comprising:

• a pan structure comprising an inner reflective surface defining a perimeter;
• a body comprising a back reflector on a bottom-side surface of said body, wherein the back reflector defines a bottom edge, said body mounted inside said pan structure such that said inner reflective surface surrounds said body;
• an end cap closing an end of said body, said end cap having a shape;
• a pan end reflector section having a first end in close proximity to said end cap and extending from said end cap to said perimeter of said pan structure, said first end of said pan end reflector section having a contour that matches said shape of said end cap;
• an elongated light source spaced from the back reflector comprising a major axis, a minor axis, a first direction perpendicular to the major axis and the minor axis, a first face positioned to face the back reflector, and a plurality of light emitting diodes (LEDs) mounted on said first face;
• wherein the back reflector comprises subregions symmetrically shaped about the major axis of said elongated light source, wherein said light source is offset from said back reflector such that said first face is entirely below said bottom edge of said back reflector in the first direction;
• and
• at least one lens plate contacting said elongated light source and said back reflector.

A light fixture, comprising:

• at least one light source comprising a mount surface and a plurality of LED light emitters on said mount surface;
• and
• a recessed lay-in fixture structure comprising a room-side area profile of at least approximately 4 ft2, said at least one light source housed within said fixture structure, said fixture structure comprising a back reflector defining a bottom edge;
• wherein said at least one light source is mounted to face upward toward a longitudinal center of said back reflector in a first direction;
• wherein a region between said mount surface and said fixture structure defines an interior cavity;
• wherein said mount surface is offset from said fixture structure such that said mount surface is entirely below said bottom edge in the first direction;
• wherein during operation of said at least one light source, said fixture structure outputs light at no less than 88% total optical efficiency with a maximum surface luminance of not greater than 32 lm/in2 and a luminance gradient of not more than 5:1.

A troffer comprising:

• a light engine comprising:
• a body defining a bottom edge and comprising a reflector comprising subregions symmetrically shaped about a major axis of the reflector;
• an elongated mount structure proximate to said back reflector and aligned with the major axis of the reflector;
• a plurality of LEDs that emit light when energized, wherein the plurality of LEDs are mounted on the elongated mount structure such that the plurality of LEDs emit light symmetrically with respect to the major axis of the reflector such that the light is received and reflected by the reflector;
• a diffuser lens assembly comprising a light transmissive portion, the light transmissive portion directly contacting at least one side of the mount surface and directly contacting the reflector, wherein the light reflected by the reflector is emitted through the diffuser lens out of the troffer;
• and
• a thin layer of phosphor applied to the reflector to provide wavelength conversion for at least a portion of the light received and reflected by the reflector.