Remote phosphor LED constructions

摘要

A white light source includes a short wavelength LED and a phosphor layer that emits light at longer visible wavelengths. A dichroic reflector transmits the longer wavelength light, and reflects some LED light onto the phosphor such that as light travels from the LED to the dichroic reflector it does not pass through the phosphor. The LED may emit blue light, and the dichroic reflector may transmit a second portion of the LED light, such that the light source output light includes both the second portion of the LED light and the longer wavelength phosphor light. The LED may be mounted on a flexible substrate having a cavity region and neighboring region, the LED being mounted in the cavity region. A dielectric layer may be thinner in the cavity region than in the neighboring region, or a hole may extend completely through the dielectric layer in the cavity region.

主权项

1. A light source, comprising:
a first ultraviolet emitting LED; a layer of phosphor material, the phosphor material adapted to emit light at longer visible wavelengths in response to excitation from the ultraviolet light emitted by the first LED; a dichroic reflector configured to reflect a first portion of the light emitted by the first LED onto the layer of phosphor material in such a way that as light propagates from the first LED to the dichroic reflector it does not pass through the layer of phosphor material, the dichroic reflector substantially transmitting light at the longer visible wavelengths; wherein the dichroic reflector transmits little to no UV light and transmits a substantial portion of blue light emitted by the phosphor material when exposed to UV excitation light.