Junction temperature measurement to optimize thermal design of LED arrays

The drive to increase electrical currents input, and to achieve high lumen output for High Brightness Light Emitting Diode (HB LED) has led to a series of thermal problems. Hence, thermal management is one of key design parameters as the temperature directly affecting the maximum light output, quality, reliability and life time. For LED arrays, the arrangement of chips will affect the thermal performance and junction temperature is very important in the design. However, because direct junction temperature determination is hard to detect due to the encapsulation, indirect methods are more preferred. Among them, the diode forward-voltage method is the most accurate one. Therefore, we used the diode forward-voltage method to optimize thermal design of LED arrays in this work.