Thermal
resistance (thermal resistance), is the object of the effects of heat
conduction obstacles. The unit of thermal resistance ℃ / W, which
continued to heat and power 1W objects, the heat conduction path to
both ends of the temperature difference. LED thermal resistance is the
LED lit, the heat conduction stability, the surface of each chip 1W
dissipation, PN junction connected to the temperature and outside the
branch plus or cooling substrate is a temperature difference between
the LED thermal resistance Rth. Commonly used thermal resistance or R
θ, said the location where the temperature Tj for the junction, Tx for
hot-position of the temperature reached a certain point, P for the
import of heat power. Heat large thermal resistance that is not easy to
transfer, so the temperature generated by packages than on the high
thermal resistance can be judged from the heat conditions and forecast
suite. ℃ / W lower the number, saying the chip the faster conduction of
heat to the outside world. Therefore, reducing the temperature of the
chip in the PN junction LED is conducive to longevity. |
