Solid state lamp using light emitting strips

A solid state lamp comprising:

• a base configured to electrically connect the solid state lamp to a power source, the base defining an axis;
• an envelope extending along the axis;
• and
• a strip inside the envelope, the strip comprising:
• a substrate;
• a plurality of spaced-apart light-emitting diode (LED) unpackaged dies disposed on a top surface of the substrate;
• conductors arranged to provide electrical power to the LED unpackaged dies;
• and
• a wavelength-conversion material optically coupled with the LED unpackaged dies,
• wherein the substrate transmits at least some light from the top surface to the bottom surface, and
• wherein the top surface faces a first side of the strip and a bottom surface of the substrate opposite the top surface faces a second side of the strip, and the strip outputs first light from the first side having a first spectral power distribution (SPD) and outputs second light from the second side having a second SPD different from the first SPD.