A lighting apparatus is described. One embodiment of the lighting apparatus includes a substrate and a lighting element. The lighting element is coupled to the substrate to emit light through a light exit plane. The light exit plane is substantially perpendicular to the substrate. By providing a lighting device with a substrate oriented perpendicular to the light exit plane of the lighting device, the lighting device can enable better mixing of the light from different LEDs. The lighting apparatus facilitates light mixing, generally, to minimize or eliminate dark spots on the diffusion panel. The lighting device also facilitates color mixing to produce relatively consistent white light on the diffusion panel.