Research On Detection Technology Of Optical Parts Edge Thickness Difference

Edge thickness difference is one of the important technical indexes of optical components in the optical system. At present, it is expensive of commercial testing instrument for adapting to wide range of focal length, and also the operation is complicated.In this paper, a instrument for testing decentration was designed and fabricated based on the position sensitive detector technology(PSD), after comparing advantages and disadvantages of transmission, reflection and interference method. Optical and optical-mechanical system were designed and fabricated completely, and assembly and debugging were also done.The main results obtained are as follows:The calculation equation for testing edge thickness difference was deduced based on analysing basic theory of testing lens decentration. Pre-focusing system was designed for a facula less than 3mm on the PSD sensitive area.The machine parts of the instrument has been designed and processed,which mainly includes five parts, such as the optical focusing part, the rotating stage, the light spot detection part, the supporting frame part and the box cover part. It is proved that the instrument is suitable for the edge thickness difference measurement of many kinds of optical components. Experiment results show that the measurement range of focus length range from ±5mm to infinity, and measurement accuracy is better than 3μm, and the repeatability is better than 1μm. Testing instrument is reliable and which can be easily used in the detection on factory production line.