With the development of the fabricating and testing technology, the large optical system is widely used in more and more
fields, the diameters of the convex aspheric mirrors are also becoming larger, generally the test of the large convex
aspheres is much more difficult. It is always urgent to research and develop new fabricating and testing technology of the
large convex aspheric components. In this paper we make a comparison of the advantages and disadvantages of the
current test methods, at this basis another test method for the large convex aspheres–aspheric test plate method is given.
The principle and test setup are explained detailedly. Using ZEMAX software we design and simulate the test plates and
the wavefront error is better than 1/50 λ(PV).
We present a method to measure the radius of curvature of a concave conic asphere. By analysis the central area of the asphere, we can measure the radius of an arbitrary point in the central area instead of the vertex of asphere. In the procedure, we firstly adjust the interferometer until the interferogram of the central area approach nulls, then put the laser tracker ball at the beam focus of the interferometer and move the tracker ball to touch the central area of the aspherical surface to get the two positions. With these measurement data, we can calculate the radius of curvature of the aspherical vertex and its uncertainty.