LED based lamp including reflective hood to reduce variation in illuminance

摘要

A lamp comprises: a thermally conductive body; a plurality of LEDs configured as an array and mounted in thermal communication with the body and a light reflective hood located in front of the plane of light emitting diodes. The hood has at least two frustoconical light reflective surfaces that surround the array of LEDs and are configured such that in operation light emitted by the lamp is within a selected emission angle (beam spread). The hood is configured such that in operation a variation in illuminance (luminous flux per unit area incident on a surface) is 10% or less over approximately a third to one half of the selected emission angle.