Optical element
First Claim
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1. An optical element, comprising:
- a substrate comprising calcium fluoride; and
a coating supported by the substrate,wherein;
the coating consists of, in order moving away from the substrate, a first layer, a second layer, a third layer, and a fourth layer;
the first layer comprises magnesium fluoride;
the second layer comprises an inorganic oxide;
the third layer comprises an inorganic fluoride;
the fourth layer comprises an inorganic oxide;
the first layer is in contact with the substrate;
the fourth layer is in contact with the surroundings of the optical element; and
the coating is an anti-reflection coating.
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Abstract
In order to make possible both good laser resistance and good antireflection properties, an optical element, in particular for UV lithography, comprising a substrate and a coating on the substrate having at least four layers, is proposed, wherein
- a first layer comprising a low refractive index inorganic fluoride compound is arranged on the substrate,
- a layer comprising an inorganic oxide-containing compound is arranged as a layer the most distant from the substrate, and
- at least two further layers each comprising an inorganic fluoride compound or an inorganic oxide-containing compound are arranged alternately between the first and the most distant layers.
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Citations
13 Claims
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1. An optical element, comprising:
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a substrate comprising calcium fluoride; and a coating supported by the substrate, wherein; the coating consists of, in order moving away from the substrate, a first layer, a second layer, a third layer, and a fourth layer; the first layer comprises magnesium fluoride; the second layer comprises an inorganic oxide; the third layer comprises an inorganic fluoride; the fourth layer comprises an inorganic oxide; the first layer is in contact with the substrate; the fourth layer is in contact with the surroundings of the optical element; and the coating is an anti-reflection coating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification