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.