| 摘要 |
PROBLEM TO BE SOLVED: To provide a device which quantitatively evaluates the errors in a measured value caused by disturbance, and reduces its measurement error to an allowance or less, on the basis of that result, in measurement using an optical interferometer. SOLUTION: A disturbance measuring device and a measuring device which uses the measured values, cause object light and reference light to have between them a phase difference which changes in the shape of a sawtooth wave, as a result cause the intensity of their interference light to change sinusoidally, in an interference optical system, measure the phase difference by utilizing that fact, and sample that phase difference by a predetermined frequency. In doing this, the frequency characteristics of the quantity of the error of the measured value caused by the disturbance can be evaluated. Moreover, the spatial distribution of the quantity of the error of the measured value caused by the disturbance can be evaluated, by dividing the interference light into two luminous fluxes, forming apertures at positions where the respective luminous fluxes correspond to different portions of a measuring object, and measuring the phase difference between the interference lights which have passed the apertures. On the basis of the result, the frequency of the phase difference in the shape of a saw toothwave necessary for attaining measurement accuracy is decided. COPYRIGHT: (C)2004,JPO
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