Patent ID: 6717679
Filing Date: 2004-04-06
Classification: G01B

Abstract:
A method for measuring aspheric surfaces and wavefronts with the use of an interferometer; said method comprising the steps of:directing a spherical wavefront of known design at a wavelength &lgr;1 at a reference sphere with known measured surface properties to generate a first electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated by the interferometer; directing an apherical wavefront of known design at a wavelength &lgr;2 at an aspherical surface or wavefront to be tested to generate a second electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated by the interferometer analyzing said first and second electronic signals and calculating therefrom wavefront error maps W1=W1(&lgr;1) and W2=W2(&lgr;2) both of which contain wavelength dependent known design and measured errors and unknown errors due to the manufacture, material composition of components in the interferometer, and systematic errors; and determining the optical path error caused by shape errors in the aspherical surface or wavefront while accounting for substantially all error sources present in the electronic signals.