| 摘要 |
PROBLEM TO BE SOLVED: To provide a device which quickly measures pupil transmittance distribution of an optical system to be measured with high accuracy and low burden.SOLUTION: A measuring apparatus 10 for measuring pupil transmittance distribution of an optical system to be measured, comprises: a diffraction grating 11 which can be installed on a first surface in an optically Fourier transform relation to a pupil of the optical system to be measured; a lighting optical system 12 for guiding a light beam inclined to an optical axis, so that positive primary diffracted light generated through the diffraction grating 11 passes through a first pupil partial area in an effective area of the pupil and negative primary diffracted light generated through the diffraction grating 11 passes through a second pupil partial area, to enter the light beam into a predetermined position of the first surface; and a measuring unit for measuring intensity of the positive primary diffracted light passed through the first pupil partial area and the optical system to be measured and intensity of the negative primary diffracted light passed through the second pupil partial area and the optical system to be measured. The measuring apparatus calculates a ratio of pupil transmittance in the first pupil partial area to pupil transmittance in the second pupil partial area, on the basis of a measured value of the intensity of the positive primary diffracted light and a measured value of the intensity of the negative primary diffracted light. |
