Solid-state light source using passive phase change cooling

摘要

A solid-state light source with light emitting diodes embedded in thermally conductive luminescent elements is cooled by immersion cooling via a phase change material (liquid or pool boiling). The thermally conductive translucent luminescent elements are arranged to confine the boiling to an inner tube with the condensed liquid on the output faces so as to provide a flicker free 360 degree output light source. At least one face of each LED is exposed directly to the fluid and the LED is unconstrained so as to provide optical emission with little to no wavelength shift as a function of drive current.

主权项

1. A solid-state light source utilizing phase change cooling, comprising:
at least one thermally conductive luminescent element; at least one light emitting diode (LED) connectable to an external power source; an outer envelope enclosing the at least one thermally conductive luminescent element and the at least one LED, the outer envelope being transparent over at least part of its surface to allow emission of light; and a quantity of cooling fluid, of which at least a substantial portion is enclosed within the outer envelope; wherein the outer envelope encloses an evaporator section in which the cooling fluid is transformed from a liquid phase to a gas phase by heat generated by the at least one LED and the at least one thermally conductive luminescent element, thereby removing heat from these elements by phase change cooling; and wherein the outer envelope also encloses a condenser section from which heat is removed and in which the cooling fluid is transformed from its gas phase back to its liquid phase, for recirculation back to the evaporator section.