| abstract |
A typical Lambertian LED die emission is modified by an optical structure formed on an LED die that reduces the light emission along the vertical axis and increases the light emission at an angle to the vertical axis to produce a specific light emission profile. A phosphor layer is provided to rest on the optical structure, for example, in a reflective light-mixing chamber. The light emission profile results in a more uniform flux from the LED die impacting over the surface of the phosphor. A portion of the LED light passes through the phosphor, and some of this light is converted to light of a different wavelength. The light emission profile results in more uniform color and temperature across the phosphor. The light emission profile may be generated by a lens, a patterned layer on the LED die, a semi-reflective layer on the LED die, an optical sheet, or other technique. |