Study on influence of integrating sphere test position on measuring accuracy of optical parameters of LED chip

The development of a system that evaluates optical parameters of light emitting diodes (LED) in a wafer is presented, equipped with an integrating sphere on a three-dimensional precision platform. The influence of integrating sphere´s (IS) position and height relative to LED chip on measuring accuracy is analyzed quantitatively. It was found that luminous flux variation was less than 0.5% within deviation and there was a 20% reduction with the relative height varying from 9cm to 11cm.