Measurement System For Testing & Binning Of Back-End LEDs

TP121-TH - Gigahertz-Optik GmbH

The photometric specifications of LEDs must meet very high tolerance requirements regardless of whether they are to be used in general, automotive or other specialist lighting applications. This is often a problem since the manufacturing tolerances of LEDs can be higher than those permitted in the end-use applications. Also, LED binning by LED manufacturers in order to classify LEDs based on their tolerances is performed with flash mode testing using pulsed current flow. However, end-use applications of the LEDs often operate in constant current mode and with significant thermal effects. The sophisticated LED processing industry therefore requires measurement devices that can be used for both manufacturer-compliant pulsed mode, as well as constant current operation mode. When the LEDs are run in constant current mode, the junction temperature has significant influence on the performance and lifetime of the LED. Therefore, test systems should be able to test the LEDs at specific junction temperatures.