Study On The Measurement Of The Spatial Position Of The Probe For Swing Arm Profilometer

With the fast development of science and technology, optical aspheric is more and more widely used in key technology areas such as large optical systems, spatial recognition and infrared seeker as well as civil photoelectric products with its excellent optical property. However, there is some difficulty in the fabrication of surface shape and in-situ measurement of optical aspheric, so the measurement method of swing arm profilometer(SAP) is proposed. The swing arm profilometer has the advantages of simple structure, low cost, big measurement range, high accuracy and capability of in-situ measurement, can achieve the in-situ measurement of optical aspheric and reduce the risk of transport, and improve the measurement accuracy of surface shape and the efficiency of fabrication. But the centering error of the probe and effective arm length of the spatial position of probe for swing arm profilometer have some influence on the measurement accuracy of surface shape in the actual measurement. The main work of this paper is the measurement of spatial position of probe of swing arm profilometer. The method of the spectral confocal sensor measuring the centering error of the probe and the joint measurement method of the point source microscope measuring the space coordinate position of the probe system and the laser tracker measuring the axis of turntable for effective arm length are proposed. The major research content is included in the following: 1. The research status of the swing arm profilometer at home and abroad are carried, the measurement principle of swing arm profilometer is introduced. The centering error of probe need be controlled in 10μm and this needs the measurement accuracy of centering error be controlled in 3μm, the measurement accuracy of effective arm length is 10μm with the analysis of the spatial position of probe. And the measurement methods of the centering error and effective arm length are introduced. 2. The method of the spectral confocal sensor measuring the centering error of the probe and the measurement principle of the spectral confocal are introduced. The measurement accuracy and the influence factors of the centering error are analyzed. The measurement accuracy is Ug L=0.8μm with the Monte-Carlo analog. 3. For the effective arm length, the measurement methods of the point source microscope measuring the space coordinate position of the probe system and the measurement principle of the laser tracker measuring the axis of turntable are introduced, also the measurement principles of the point source microscope and the laser tracker are introduced. The measurement accuracy of effective arm length is UL=8.2μm with the Monte-Carlo analog. 4. The contrastive experiments are built for the accuracy of the spectral confocal sensor measuring the centering error of the probe for swing arm profilometer, the feasibility and reliability of the measurement method is proved with the results of the contrastive experiments. 5. The contrastive experiments are built for the accuracy of the experiments of the space coordinate position of the probe system and the axis of turntable for effective arm length of swing arm profilometer, the feasibility and reliability of the measurement method is proved.