| 摘要 |
PURPOSE:To achieve a higher measuring accuracy, by separating a luminous flux from an object to be inspected in two to make the one luminous flux shear to the other. CONSTITUTION:A luminous flux from an object to the inspected is separated in two and then, one of the two luminous fluxes is made to shear to the other thereof in the direction (x). Under such a condition, shearing value Sx, shearing error DELTASy in the direction Sy and phase difference DELTAWx between the wave fronts of these luminous fluxes are determined. Then, one of the two luminous fluxes is made to shear the other in the direction (y). Under such a condition, shearing value Sy, shearing error DELTASx in the direction Sx and the phase difference DELTAWy between the wave fronts of two luminous fluxes are determined. In this manner, shearing values Sx and Sy, errors DELTASx and DELTASy and phase differences DELTAWx and DELTAWy are determined and are used to determine the x-way wave front shape W(x) and the y-way wave front shape W(y) by the formula. Then, from the wave front shapes W(x) and W(y), a 3-D wave front shape W(x,y) is determined by computation. |
