Wavefront measuring method and wavefront measuring apparatus using the wavefront measuring method
AssigneeCanon Kabushiki Kaisha
InventorsSatoru Komatsu, Yasuhiro Sawada
Life of this patent
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Abstract
A wavefront measuring method includes steps of: obtaining a first transmitted-wavefront from a first image formed by transmitting beam through a substance at a first angle; obtaining a second image formed by transmitting the beam through the substance at a second angle; formulating a mask corresponding to an interference degree of the second image; converting the first transmitted-wavefront to match with a temporary second transmitted-wavefront from the second image; and unwrapping from the second image, the mask, and a converted first transmitted-wavefront to obtain a second transmitted-wavefront by transmitting the beam through the substance at the second angle.
Claims10
A wavefront measuring method comprising:
- a first obtaining step for obtaining a first two-dimensional phase image or a first transmitted wavefront based on a transmitted light beam when a light beam is made incident into an inspected substance at a first angle;
- a second obtaining step for obtaining a second interference fringe image formed based on a transmitted light beam when a light beam is made incident into the inspected substance at a second angle different from the first angle;
- a mask generating step for generating a mask corresponding to an interference degree of the second interference fringe image;
- a converting step for converting the first two-dimensional phase image to match with a temporary second two-dimensional phase image obtained based on the second interference fringe image or converting the first transmitted wavefront to match with a temporary second transmitted wavefront obtained based on the second interference fringe image;
- and
- an unwrapping step for unwrapping based on (1) the second interference fringe image, the mask, and the first two-dimensional phase image converted in the converting step, or (2) the second interference fringe image, the mask, and the first transmitted wavefront converted in the converting step, to obtain a second transmitted wavefront by a light beam transmitted through the inspected substance when a light beam is made incident into the inspected substance at the second angle.
A wavefront measuring apparatus configured to measure a transmitting wavefront of a light beam made incident into the inspected substance at a second angle, the apparatus comprising:
- a first obtaining unit which obtains a first two-dimensional phase image or a first transmitted wavefront based on a transmitted light beam when the light beam is made incident into the inspected substance at a first angle;
- a second obtaining unit which obtains a second interference fringe image formed based on a transmitted light beam when a light beam is made incident into the inspected substance at the second angle different from the first angle;
- a mask generating unit which generates a mask corresponding to an interference degree of the second interference fringe image;
- a converting unit which converts the first two-dimensional phase image to match with a temporary second two-dimensional phase image obtained based on the second interference fringe image or converting the first transmitted wavefront to match with a temporary second transmitted wavefront obtained based on the second interference fringe image;
- and
- an unwrapping unit which unwraps based on (1) the second interference fringe image, the mask, and the first two-dimensional phase image converted in the converting unit, or (2) the second interference fringe image, the mask, and the first transmitted wavefront converted by the converting unit, to obtain a second transmitted wavefront by a light beam transmitted through the inspected substance when a light beam is made incident into the inspected substance at the second angle.
Dependencies are inferred from the claim text.