A novel phase measuring deflectometry for aspheric mirror test.

ABSTRACT

A method based on fringe reflection is presented to measure the aspheric mirror with higher precise. This method measures the absolute height of the aspheric mirror with dummy paraboloid, while the camera is located beside the optical axis of the test surface. It can be used to measure the aspheric mirror with high deviation. And for locating the camera beside the optical axis, this method doesn't have occlusion problem and can do the measurement more flexibility. Furthermore, compared with the traditional PMD, this method measures the tested surface with dummy paraboloid instead of the intersection of two straight lines, so it doesn't need to calibrate the image projection vectors. And the errors of the calibration influence this method less than the traditional method. Therefore, this method can measure the high deviation aspheric mirror with higher precise even if the calibration precise isn't very high. Computer simulations and preliminary experiment validate the feasibility of this method.