Diffraction optical element
First Claim
1. A diffraction optical element comprising:
- a first diffraction grating made of a resin material in which inorganic fine particles are dispersed; and
a second diffraction grating made of a material whose organic matter composition is substantially same as organic matter composition of the resin material, wherein a maximum difference of optical path lengths of light passing through the diffraction optical element is integer multiples of a plurality of wavelengths.
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Accused Products
Abstract
In a diffraction optical element in which a plurality of diffraction gratings are laminated and the maximum difference of length among optical paths of light passing through the plurality of diffraction gratins is integer multiples of a plurality of wavelengths, diffraction efficiency is further improved and even when an environmental condition changes, a deviation of the diffraction efficiency is reduced. More specifically, a diffraction optical element is disclosed which includes, as the plurality of diffraction gratings, a first diffraction grating made of a resin material, in which inorganic fine particles are dispersed, and a second diffraction grating made of a material whose organic matter composition is substantially same as that of the resin material.
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Citations
16 Claims
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1. A diffraction optical element comprising:
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a first diffraction grating made of a resin material in which inorganic fine particles are dispersed; and
a second diffraction grating made of a material whose organic matter composition is substantially same as organic matter composition of the resin material, wherein a maximum difference of optical path lengths of light passing through the diffraction optical element is integer multiples of a plurality of wavelengths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A diffraction optical element comprising:
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a first diffraction grating made of a first material that is a resin material in which inorganic fine particles are dispersed; and
a second diffraction grating made of a second material having an optical characteristic different from that of the resin material in which the inorganic fine particles are dispersed, wherein a maximum difference of optical path lengths of light passing through the diffraction optical element is integer multiples of a plurality of wavelengths, and wherein each of the first material and the second material satisfies at least one of the following conditions;
0.8≦
dn1/dt/dn2/dt≦
1.25,
0.8≦
α
1/α
2<
1.25,
0.8≦
β
1/β
2<
1.25,where dn1/dt and dn2/dt are respectively refractive index changes with respect to a temperature deviation of the first material and the second material, α
1 and α
2 are respectively linear expansion coefficients of the first material and the second material, and β
1 and β
2 are respectively swelling ratios of the first material and the second material. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification