Abstract: The optical element includes a base member configured to have an optical surface, a concave-convex structure configured to have an average pitch smaller than a shortest wavelength of a use wavelength range, and an intermediate layer formed between the optical surface and the concave-convex structure, made of a material different from that of the concave-convex structure, and having a refractive index between those of the base member and the material of the concave-convex structure. The optical surface is formed into a shape having a rotational symmetry axis. A thickness of the intermediate layer or each of thicknesses of the intermediate layer and the concave-convex structure varies so as to increase as a distance from the rotational symmetry axis increases. The optical element has good anti-reflection performance not only at a central part of the optical surface having a small curvature radius but also at a peripheral part thereof.

Abstract: An optical element that has a fine textured structure formed on an exit surface thereof. The fine textured structure satisfies the following conditions: ?min/1.71nsub<p<?min/2 and 0.6?min<h<1.5?min, where ?min is the shortest wavelength used in the optical element, nsub is the refractive index of a substrate on which the fine textured structure is formed, p is the pitch of the fine textured structure, and h is the height of the fine textured structure. The textured structure includes a part where some rays incident parallel to the optical axis are totally reflected.

Abstract: It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO2 as a main component, a layer containing Al2O3 as a main component, and a plate crystal layer formed from plate crystals containing Al2O3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.

Abstract: An optical element includes an optically effective area and an optically ineffective area partly or entirely coated with a coating opaque at wavelengths used. The opaque coating contains a cured product prepared from an epoxy resin and a curing agent containing an alicyclic acid anhydride. The alicyclic acid anhydride is preferably methylhexahydrophthalic anhydride or hexahydrophthalic anhydride.

Abstract: It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO2 as a main component, a layer containing Al2O3 as a main component, and a plate crystal layer formed from plate crystals containing Al2O3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.

Abstract: The optical element includes in order from a light-entering side, a first layer (012), a second layer (013), and a base member (011). The first layer includes a concavo-convex structure with convex portions (012a) and concave portions (012b) alternately formed at a pitch smaller than a wavelength ? of entering light, and the second layer satisfies the following conditions: nb · n ? ? s - 0.15 ? n ? ? A ? nb · n ? ? s + 0.10 ? 8 · n ? ? A ? dA ? ? n ? ? A where ns represents an effective refractive index of the first layer, nb represents a refractive index of the base member, and nA and dA respectively represent a refractive index and a thickness of the second layer.

Abstract: An optical element that has a fine textured structure formed on an exit surface thereof. The fine textured structure satisfies the following conditions: ?min/1.71nsub<p<?min/2 and 0.6?min<h<1.5?min, where ?min is the shortest wavelength used in the optical element, nsub is the refractive index of a substrate on which the fine textured structure is formed, p is the pitch of the fine textured structure, and h is the height of the fine textured structure. The textured structure includes a part where some rays incident parallel to the optical axis are totally reflected.

Abstract: Provided is an optical system with an excellent anti-reflection effect and ghost suppression effect including an aspherical lens having at least one of an incident surface and an exiting surface of an optical glass formed of an aspherical surface, in which: the aspherical surface includes an anti-reflection structure formed thereon, the anti-reflection structure having an anti-reflection function and including multiple inorganic structural parts finer than a used wavelength; and the aspherical surface has a point that satisfies the following expression: |(1/Rm?1/Rs)/Rm|>5.0×10?5, where Rm denotes a radius of curvature in a meridional direction at an arbitrary point, and Rs denotes a radius of curvature in a sagittal direction at the arbitrary point.

Abstract: It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO2 as a main component, a layer containing Al2O3 as a main component, and a plate crystal layer formed from plate crystals containing Al2O3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.

Abstract: An optical element includes an optical surface formed by a press molding method, wherein a ray effective portion of the optical surface has formed thereon an antireflection structure including a minute uneven structure, which contains a component different from that of a base of the optical element and has an average pitch of 400 nm or less.

Abstract: The optical element includes in order from a light-entering side, a first layer (012), a second layer (013), and a base member (011). The first layer includes a concavo-convex structure with convex portions (012a) and concave portions (012b) alternately formed at a pitch smaller than a wavelength ? of entering light, and the second layer satisfies the following conditions: nb · n ? ? s - 0.15 ? n ? ? A ? nb · n ? ? s + 0.10 ? 8 · n ? ? A ? dA ? ? n ? ? A where ns represents an effective refractive index of the first layer, nb represents a refractive index of the base member, and nA and dA respectively represent a refractive index and a thickness of the second layer.

Abstract: The optical element includes a base member configured to have an optical surface, a concave-convex structure configured to have an average pitch smaller than a shortest wavelength of a use wavelength range, and an intermediate layer formed between the optical surface and the concave-convex structure, made of a material different from that of the concave-convex structure, and having a refractive index between those of the base member and the material of the concave-convex structure. The optical surface is formed into a shape having a rotational symmetry axis. A thickness of the intermediate layer or each of thicknesses of the intermediate layer and the concave-convex structure varies so as to increase as a distance from the rotational symmetry axis increases. The optical element has good anti-reflection performance not only at a central part of the optical surface having a small curvature radius but also at a peripheral part thereof.

Abstract: It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO2 as a main component, a layer containing Al2O3 as a main component, and a plate crystal layer formed from plate crystals containing Al2O3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.

Abstract: An optical system includes an optical element formed of resin. On at least one of optical surfaces on the light incidence side of the optical element formed of resin, a plurality of depressions or protrusions of a size not larger than the wavelengths of visible light is formed without a periodic structure or in a random arrangement.

Abstract: It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO2 as a main component, a layer containing Al2O3 as a main component, and a plate crystal layer formed from plate crystals containing Al2O3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.

Abstract: A diffractive optical element in which eclipse of rays at a grating side surface of a diffraction grating can be reduced is disclosed. In a diffractive optical element comprises a plurality of diffraction gratings made of different materials are laminated, at least one of the plurality of diffraction gratings includes a region in which the grating side surface inclines or a region in which edges thereof are shifted with respect to the edge of another diffraction grating adjacent thereto. The inclination or shift amount is different according to the positions thereof in a surface of the diffractive optical element in accordance with the incident angle or emergent angle of a specified ray such as a ray determined on the basis of an average value, gravity value, maximum value and minimum value obtained from the distribution of incident angle or emergent angle or the like, rays, etc.

Abstract: Disclosed is a diffractive optical element which includes a plurality of diffraction gratings being made of materials having different dispersions and being formed in accumulation, wherein at least one of the diffraction gratings has a varying grating thickness.

Abstract: An optical element includes a substrate; a first diffraction grating disposed on the substrate and having a period that is shorter than a light wavelength used; and a second diffraction grating disposed on the first diffraction grating and having a period that is shorter than the light wavelength used. In the optical element, the melting point of a material of the first diffraction grating is higher than the melting point of a material of the second diffraction grating.

Abstract: A diffractive optical element in which eclipse of rays at a grating side surface of a diffraction grating can be reduced is disclosed. In a diffractive optical element comprises a plurality of diffraction gratings made of different materials are laminated, at least one of the plurality of diffraction gratings includes a region in which the grating side surface inclines or a region in which edges thereof are shifted with respect to the edge of another diffraction grating adjacent thereto. The inclination or shift amount is different according to the positions thereof in a surface of the diffractive optical element in accordance with the incident angle or emergent angle of a specified ray such as a ray determined on the basis of an average value, gravity value, maximum value and minimum value obtained from the distribution of incident angle or emergent angle or the like, rays, etc.

Abstract: Disclosed is a diffractive optical element which includes a plurality of diffraction gratings being made of materials having different dispersions and being formed in accumulation, wherein at least one of the diffraction gratings has a varying grating thickness.