Remote phosphor LED device with broadband output and controllable color

摘要

A broadband light source includes a phosphor layer excited by light from multiple LEDs. A dichroic reflector reflects light from the LEDs onto the phosphor layer. First and second LEDs are responsible for first and second broadband portions respectively of a broadband output light of the source, each such broadband portion being broadband and nominally white. The device components are configured and arranged so that the first and second broadband light portions have different CIE color coordinates. These portions combine to yield a resultant color for the overall broadband light output of the source, which resultant color is a function of the relative amounts of the first and second broadband light portions. An open-loop or closed-loop controller can independently drive the LEDs to provide a desired mix of the broadband light portions so that the overall broadband light output has a color in a desired design space.

主权项

1. A light source for emitting broadband output light, comprising:
a first and second LED adapted to emit first and second LED light respectively; a layer of phosphor material adapted to emit first longer wavelength phosphor light in response to excitation from light emitted by the first LED and second longer wavelength phosphor light in response to excitation from light emitted by the second LED; and a dichroic reflector configured to reflect at least a portion of the first LED light, and at least a portion of the second LED light, onto the layer of phosphor material in such a way that as light propagates from the first and second LEDs to the dichroic reflector it does not pass through the layer of phosphor material, the dichroic reflector substantially transmitting light at the first and second longer wavelengths so that such transmitted first and second longer wavelength phosphor light is included in the broadband output light of the light source; wherein the first longer wavelength phosphor light and optionally a remaining portion of the first LED light provide a first broadband light portion for the light source, and the second longer wavelength phosphor light and optionally a remaining portion of the second LED light provide a second broadband light portion for the light source, the broadband output light of the light source comprising the first and second broadband light portions; and wherein the first broadband light portion has a first color, and the second broadband light portion has a second color that differs from the first color.