DEVELOPMENT OF A FULLY AUTOMATED LED LIFETIME TEST SYSTEM

摘要

A fully automated system for light-emitting diode (LED) lifetime test has been developed and is undergoing validation. This system uses a 1 m integrating sphere for both ageing and optical measurements of 480 LEDs. It features six test zones, each of which holds an LED load board with 80 LEDs. Each zone operates independently, executing a user-entered recipe that defines current (to 5 A), voltage (to 200 V), mode (continuous on, pulsing, or cycling), and temperature (from 25°C to 115°C). LED ageing and light measurement occurs without the requirement to move the LED load board since the Thermal Electric Cooler (TEC) based temperature zones are enclosed within the sphere. This fully automated system addresses several challenges inherent with existing methods that require costly labour to move LED load boards from thermal control chambers to light measurements spheres. Using the new system, frequent light measurements are possible with small measurement uncertainties and a reduced operating cost. The fully automated LED lifetime test system is designed to operate for 3 - 5 years, producing long-term luminous flux depreciation data that can be applied to validate existing lifetime models and to develop new models for predicting LED lifetime.