POLARIZATION CONVERTING UNIT, ILLUMINATION OPTICAL SYSTEM, EXPOSURE APPARATUS, AND DEVICE MANUFACTURING METHOD
First Claim
1. A polarization converting unit arranged on an optical axis of an optical system and configured to convert a polarization state of propagating light passing along an optical-axis direction corresponding to the optical axis, the polarization converting unit comprising:
- a first optically rotatory member to rotate linearly polarized light incident thereto as the propagating light, around the optical-axis direction, the first optically rotatory member being comprised of an optical material with an optical activity, which is arranged so as to have a crystal axis coincident or parallel with the optical-axis direction, and having a first thickness distribution of thicknesses in the optical-axis direction different at a plurality of locations; and
a second optically rotatory member to rotate linearly polarized light incident as the propagating light thereto through the first optically rotatory member, around the optical-axis direction, the second optically rotatory member being comprised of an optical material with an optical activity, which is arranged so as to have a crystal axis coincident or parallel with the optical-axis direction, and having a second thickness distribution of thicknesses in the optical-axis direction different at a plurality of locations,wherein the first and second optically rotatory members are arranged so that the sum of respective thicknesses in the optical-axis direction at predetermined locations in the first and second optically rotatory members through which a first reference axis parallel to the optical-axis direction passes is different from the sum of respective thicknesses in the optical-axis direction at other locations in the first and second optically rotatory members through which a second reference axis parallel to the optical-axis direction and different from the first reference axis passes.
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Accused Products
Abstract
According to one embodiment, a polarization converting unit, for converting incident light into light in a predetermined polarization state and emitting the converted light, has a first optically rotatory member having a first thickness distribution of thicknesses in an optical-axis direction different at a plurality of locations and a second optically rotatory member having a second thickness distribution, each of which is a member to rotate linearly polarized light incident thereto as propagating light, around the optical-axis direction. The first and second optically rotatory members are comprised of an optical material with an optical activity arranged so as to have a crystal axis coincident or parallel with the optical-axis direction. Particularly, the sum of respective thicknesses of superimposed regions in the first and second optically rotatory members is different from the sum of respective thicknesses of other superimposed regions in the first and second optically rotatory members when viewed along the optical-axis direction.
125 Citations
23 Claims
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1. A polarization converting unit arranged on an optical axis of an optical system and configured to convert a polarization state of propagating light passing along an optical-axis direction corresponding to the optical axis, the polarization converting unit comprising:
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a first optically rotatory member to rotate linearly polarized light incident thereto as the propagating light, around the optical-axis direction, the first optically rotatory member being comprised of an optical material with an optical activity, which is arranged so as to have a crystal axis coincident or parallel with the optical-axis direction, and having a first thickness distribution of thicknesses in the optical-axis direction different at a plurality of locations; and a second optically rotatory member to rotate linearly polarized light incident as the propagating light thereto through the first optically rotatory member, around the optical-axis direction, the second optically rotatory member being comprised of an optical material with an optical activity, which is arranged so as to have a crystal axis coincident or parallel with the optical-axis direction, and having a second thickness distribution of thicknesses in the optical-axis direction different at a plurality of locations, wherein the first and second optically rotatory members are arranged so that the sum of respective thicknesses in the optical-axis direction at predetermined locations in the first and second optically rotatory members through which a first reference axis parallel to the optical-axis direction passes is different from the sum of respective thicknesses in the optical-axis direction at other locations in the first and second optically rotatory members through which a second reference axis parallel to the optical-axis direction and different from the first reference axis passes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification