- High-power/brightness LED's in HD projection applications provide enhanced color range, high performance over the life of the end product and lower cost compare to current arc lamp technology. In the same time, that high power density of the LED makes it challenging for the air cooled application. Insufficient cooling of LED chips for the high brightness applications limits the ability to achieve continuously bright (not flickering) image.

Since an LED's service life could be up to 60,000 hrs, enabling it’s efficient cooling not only positively impacts the overall system reliability, but dramatically improves it’s brightness and color intensity, i.e. the competitiveness of the product. A liquid cooling system for LED application should never leak (not water), be compact, highly efficient and self regulating with changing LED power.

This superior cooling could be achieved by cooling with hermetic, highly efficient and compact PLMC systems. It’s very low thermal resistance, virtually not changing (for the properly selected refrigerant flow rate), allows to achieve outstanding thermal results for high ambient temperatures and reasonable air flows.

Table 1 illustrates experimentally verified results for one of the high performance LED projectors with TF&F PLMC cooling system:

Pulse Drive Current Blue Green Red   Power applied to LEDs 51.2 104.5 34.3 W Power all panels 190.0     W Design Safety Factor (predicted) 1.42 1.04 1.11   Topmax 120.0 130.0 80.0 °C Tjmax 84.7 124.9 71.9 °C Rj-b (0,61 °C/W) -0.61 -0.61 -0.61 °C/W Tboard 53.4 61.2 51.0 °C TIM (0,12 °C/W) -0.12 -0.12 -0.12 °C/W Tsink 47.3 48.6 46.9 °C Cold Plate -0.025 -0.025 -0.025 °C Refrigerant 46.0 46.0 46.0 °C R Condenser (per CFD) -0.12 -0.06 -0.17 °C/W Ambient 40.0 40.0 40.0 °C

In two-phase cooling systems the latent cooling reserve in the refrigerant flow allows it to maintain almost the same cold plate temperatures even if connected in series. That also addresses rapid response to heat source power changes - without complex and costly adaptive control systems.

The LED unit is directly attached to the system cold plate.

This completely operable stand-alone PLMC unit with LED's attached awaits being attached to the projector module.

Here the PLMC cold plates have been assembled to the LED's digital micro-mirrored emitter (black box).

Here the PLMC/projector module has been installed in the LED cabinet.