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The stylus profiler is a conventional instrument in surface topography measurement. The interferometric stylus profiler which uses cylindrical phase grating as standard obtains the surface topography information via measuring the changes of phase. In this way, it is apt to realize wider range, higher accuracy and higher resolution simultaneously in topography measurement. Currently, cylindrical phase grating is ordinarily fabricated by means of holographic record. Subject to the present method and technics, the microstructure parameters of the grating, such as spatial frequency, groove depth and duty cycle can hardly been uniform in every area of grating. Concerning the working principle of interferometric stylus profiler with cylindrical phase grating as sensor, the quality of cylindrical hologram phase grating (80mm in radius of curvature, 1200lp/mm in center spatial frequency) is analyzed comprehensively in this paper. Effects of the inconsistency distribution of microstructure parameter of grating over cylinder surface on the phase difference between ±1st order diffraction wave-fronts in different incidence angle are discussed in detail. The theoretical analysis and numerical calculation results show that: the holographic recording parameters determine the distribution of spatial frequency of cylindrical hologram phase grating; the inconsistency of spatial frequency on the cylinder surface is the primary cause affecting measurement accuracy; the inconsistency of duty cycle of grating will have influence on measurement accuracy when the incidence angle is not equal to zero (i.e.in a small incidence angle). Therefore, the process tolerances of cylindrical phase grating are presented and a new fabrication method of high precision cylindrical phase grating is proposed.
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