Patent ID: 8794791

Claim:
A light-emitting-diode-based (LED-based) light bulb, comprising: a bulb; a housing, wherein the bulb is disposed on the housing; a base, wherein the housing is disposed on the base, and wherein the base is configured to make electrical contact of a power source; and an LED assembly, wherein the LED assembly includes an upper substrate for supporting one or more upper LED emitters and a lower substrate for supporting a plurality of lower LED emitters, wherein the lower substrate is at the same level as, or higher than, an interface between the bulb and the housing, and wherein the LED assembly also includes a reflective surface extending between an outer edge of the upper substrate and an inner edge of the lower substrate, wherein the reflective surface is configured to direct at least a portion of light generated by the lower LED emitters toward a backside of the LED-based light bulb, and wherein the reflective surface has a surface profile between the upper substrate and the lower substrate, the surface profile comprising a saw-patterned, or roughened profile, and wherein the inner edge of the lower substrate has a first radius and the outer edge of the upper substrate has a second radius, and wherein a ratio of the first radius to the second radius is in a range from about 0.4 to about 0.95.