1. A light emitting device comprising:a support structure;
a light emitting diode (LED) die mounted on the support structure,
the LED die having a top surface and at least one side surface and comprising LED semiconductor layers and a transparent substrate, the LED semiconductor layers having a thickness and the transparent substrate having a thickness, the substrate comprising the top surface of the LED die, a ratio of substrate thickness to the LED semiconductor layers thickness being 2 or greater and the ratio of the area of the side surface to the area of the top surface being 1 or greater;
a phosphor layer covering the top surface and side surfaces;
a reflector surrounding the LED die, the reflector having curved surfaces surrounding the LED, wherein the curved surfaces extend from a generally rectangular opening for the LED die and reflect the light from the side surfaces of the LED die to form a generally rectangular beam;
a generally rectangular lens affixed to walls of the reflector, the lens having a generally rectangular convex surface extending toward the LED die and a flat top surface facing away from the LED die; and
a thickness from a bottom surface of the support structure to the flat top surface of the lens being 2 mm or less.