Abstract: An optical element includes a plurality of substrates, an adhesive configured to adhere the plurality of substrates to each other, and an antireflection film provided to at least one of an incident surface and an exit surface of the optical element. The antireflection film includes a first layer including alcohol having at least one of an ether bond and an ester bond in a branched structure with 4 to 7 carbon atoms. A content of the alcohol in the first layer is 0.5 mg/cm3 to 5.0 mg/cm3. The first layer has a refractive index of 1.1 to 1.3 for light with a wavelength of 550 nm.

Abstract: A control apparatus includes a controller configured to instruct an image pickup apparatus that includes an image pickup element configured to capture an image formed by an optical system to capture a plurality of images in different polarization directions, and to obtain polarization information based on the plurality of images. The controller instructs the image pickup apparatus to capture the plurality of images on exposure conditions different from one another while setting constant an F-number of the optical system.

Abstract: An optical element includes a plurality of substrates, an adhesive configured to adhere the plurality of substrates to each other, and an antireflection film provided to at least one of an incident surface and an exit surface of the optical element. The antireflection film includes a first layer including alcohol having at least one of an ether bond and an ester bond in a branched structure with 4 to 7 carbon atoms. A content of the alcohol in the first layer is 0.5 mg/cm3 to 5.0 mg/cm3. The first layer has a refractive index of 1.1 to 1.3 for light with a wavelength of 550 nm.

Abstract: A control apparatus includes a controller configured to instruct an image pickup apparatus that includes an image pickup element configured to capture an image formed by an optical system to capture a plurality of images in different polarization directions, and to obtain polarization information based on the plurality of images. The controller instructs the image pickup apparatus to capture the plurality of images on exposure conditions different from one another while setting constant an F-number of the optical system.

Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: An antireflection coating film formed on an optical base member includes: a first layer having a refractive index of N1 and a film thickness of D1; a second layer having a refractive index of N2 and a film thickness of D2; and a third layer formed of a fine concavo-convex structure, having a refractive index changing from N3 to 1.0, and a film thickness of D3, wherein the first, second, and third layer are formed in order from the optical base member side having a refractive index of Nsub, and wherein when the refractive indexes Nsub, N1, N2, and N3 are those taken when a wavelength is 550 nm, conditions for Nsub, N1, D1, N2, D2, N3 and D3 are satisfied.

Abstract: Provided is an optical system having at least two or more lenses, wherein at least one of the lenses comprises an anti-reflection film formed by a wetting method on a part of or the entirety of the light beam effective surface thereof, and wherein at least one of the lenses other than the lens comprising the anti-reflection film is fixed to the space between the lens and a barrel for holding the lens via an energy-curable resin to be filled therein.

Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: An optical element includes a transparent substrate and an antireflection coating on the substrate. The antireflection coating includes an intermediate layer on the substrate, and an undulation layer that is formed on the intermediate layer and has a plurality of convexes arrayed with spacing shorter than a shortest wavelength. The undulation layer has a portion where refractive index increases from a light incident side to the substrate. The intermediate layer has a first layer closest to the substrate, and a second layer formed on the first layer. A refractive index n1 of the first layer, a refractive index n2 of the second layer, and a refractive index ns of the substrate satisfy the following conditional equations: 1.75?ns?2.20; n1<n2; and n1<ns.

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: An optical element includes a transparent substrate and an antireflection coating on the substrate. The antireflection coating includes an intermediate layer on the substrate, and an undulation layer that is formed on the intermediate layer and has a plurality of convexes arrayed with spacing shorter than a shortest wavelength. The undulation layer has a portion where refractive index increases from a light incident side to the substrate. The intermediate layer has a first layer closest to the substrate, and a second layer formed on the first layer. A refractive index n1 of the first layer, a refractive index n2 of the second layer, and a refractive index ns of the substrate satisfy the following conditional equations: 1.75?ns?2.20; n1<n2; and n1<ns.

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: An antireflection coating film formed on an optical base member includes: a first layer having a refractive index of N1 and a film thickness of D1; a second layer having a refractive index of N2 and a film thickness of D2; and a third layer formed of a fine concavo-convex structure, having a refractive index changing from N3 to 1.0, and a film thickness of D3, wherein the first, second, and third layer are formed in order from the optical base member side having a refractive index of Nsub, and wherein when the refractive indexes Nsub, N1, N2, and N3 are those taken when a wavelength is 550 nm, conditions for Nsub, N1, D1, N2, D2, N3 and D3 are satisfied.

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: 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 of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: Provided is an optical system having at least two or more lenses, wherein at least one of the lenses comprises an anti-reflection film formed by a wetting method on a part of or the entirety of the light beam effective surface thereof, and wherein at least one of the lenses other than the lens comprising the anti-reflection film is fixed to the space between the lens and a barrel for holding the lens via an energy-curable resin to be filled therein.

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 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.