| 摘要 |
A radiation distribution measurement system (10') for measuring a phase distribution of a beam of radiation and/or a pupil distribution of a projection system (PS) includes a transparent carrier plate (20), a grating and/or a pinhole (70) configured at a first side of the transparent carrier plate, and a camera (24) at an opposite side of the transparent carrier plate. The measurement system also includes a radiation filter (30) between the transparent carrier plate and the camera, with a transmissivity that is lowest at the center of the filter and gradually and concentrically increases towards the outside of the filter. By placing the filter with its specific transmissivity, the difference in intensity across the wave front sensor (10') (i.e. the gradient in intensity) is compensated. The intensity of the light incident on the camera is made more uniform resulting in an improved performance of the measurement system.
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