The Design Of Large Diameter Confocal Profiler And The Research On Dynamic Compound Scanning Method

With the continuous development of modern detection techniques of large-diameter detection optical element,various kinds of contemporary optical,mechanical and electrical components move toward to the direction of element downsizing and precision,so that the measurement accuracy requirement of profile element even elevated to the order of nanometers,and appears diversified trend,all kinds of large diameter optical components with complex surface and ultra-high performance have been available,in which the large diameter optical components played a key role in the field of astronomy optics,space optics,far field target detection,laser transmission and other fields,but also become the products.of optical system design and ultra-precision processing technology combined with each other.The title is named‘Research on dynamic compound scanning confocal measurement of large diameter optical element',the two-dimensional contour measurement and extraction of large-diameter optical element is realized by using the principle of confocal scanning.The method of changing the XZ relative motion mode to realize the faster measurement of large-diameter two-dimensional contour is studied emphatically.Based on the preparation,we write the LabVIEW computer software platform.My main job content is as follows:(1)Study the basic confocal imaging theory and analyze the three-dimensional intensity point spread function of confocal scanning imaging under the condition of dynamic composite scanning.We mainly study the changes of axial motion curve of composite motion,including different surface types and different motion modes Under the change and the impact of the latter on the measurement.(2)Taking part into the design of large-aperture optical confocal profiler,the triaxial stroke of 200×200×150mm can meet the needs of contour measurement of large-diameter optical components.The results of the step-by-step scanning and composite scanning contours can be obtained by changing the relative motion modes for different measurement facets.The instrument also has the ability of microstructure three-dimensional morphology measurement of traditional confocal measurement.(3)Large diameter optical confocal profiler geometric error modeling and correction.The Confocal Profiler is designed using a cylindrical coordinate profiler structure model.The measurement sensor uses a confocal optical probe.The position feedback uses a precision laser interferometer to monitor high precision flat crystal,The instrument measurement and monitoring system consists of four precision laser interferometer and two flat crystal,by analyzing the three-axis 18 motion error motion model and give the compensation expression,so that finishing the latter part of the compensation correction.(4)The researsh of the measurement results of the plane,the inclined surface and the spherical surface are compared with the step scanning,and the contrast between the contour repeatability measurement and the fitting result is given.and the profilometer measurement performance is analyzed.