A lamp envelope is provided with an alumina layer and a multilayer
phosphor coating on the alumina layer. The phosphor coating includes a
top phosphor layer with a first weight percent of rare earth activators
and a middle phosphor layer with a second weight percent of rare earth
activators. The second weight percent is less than the first weight
percent so that a total amount of the activators in the coating is
reduced while maintaining a required lamp brightness and color rendering
index (CRI). Preferably, the second weight percent is about 50-60% of the
first weight percent and the middle layer is about 30-50% of a total
weight of the coating so that a total weight of the activators in the
coating is no more than about 80% of a weight of the activators in the
coating if the first and second weight percents were the same.