LEDs as light sources for illumination have greatly improved, enabling applications for so-called general light purposes, as opposed to the prior use as warning lights, for example. While LEDs now approach the performance level of traditional light sources, they require the heat-dissipaters to maintain their light output and expected life times. While this problem (heat removal) is not great when low-power LEDs (below 0.5 watts) are used, it becomes a serious problem in applications that call for high power density.
Typically, heat dissipation is dealt with by a variety of means, such, for example, as substantial heat sinks; forced convection, circulating cooling liquid; heat pipes; or various combinations of these devices.
For example, U.S. Pat. No. 6,910,794 discloses an automotive lighting assembly that includes a metal heat pipe using an evaporation area and condensing area located remote from the evaporation area. Such structures are relatively massive and difficult to fabricate.
Other, large scale heat pipes have also been proposed, for large scale cooling operations, for example, those shown in U.S. Pat. Nos. 2,350,348 and 3,229,759; however, these relatively massive devices are virtually incompatible with small scale LEDs and, moreover, do not provide for direct LED mounting.