Abstract: An optical filter has a substrate, a refractive index adjusting layer on the substrate, a characteristic improving layer having a stress adjustment function on the refractive index adjusting layer, and an optical multilayer film on the characteristic improving layer, wherein the refractive index adjusting layer is constituted by one to three layers, and the characteristic improving layer is a single-layer film whose physical film thickness is 600 nm or more. The optical filter whose substrate has small warpage and which has a good spectral characteristic is provided.

Abstract: Provided is an infrared cut filter including: an infrared absorbing layer of a transparent resin containing an infrared absorber; and a selected wavelength cut layer stacked on the infrared absorbing layer, wherein the following requirements are satisfied. (i) In a spectral transmittance curve for an incident angle of 0°, an average transmittance in a 450-600 nm range is 80% or more, a transmittance in a 700-1200 nm range is 2.0% or less, and D0 represented by the following expression is less than 0.04. D0 (%/nm)=(Tmax·0?Tmin·0)/(?(Tmax·0)??(Tmin·0)) (ii) wherein a spectrum transmittance curve for an incident angle of 30°, an average transmittance in the 450 to 600 nm range is 80% or more, a transmittance in the 700-1200 nm range is 2.0% or less, and D30 represented by the following expression is less than 0.04.

Abstract: There are provided an optical filter excellent in weather resistance and a method for manufacturing an optical filter. The optical filter of the present invention includes a transparent substrate, and an optical multilayer film provided on a surface of the transparent substrate. In the optical multilayer film, a low-refractive index film containing silicon oxide (SiO2) and a high-refractive index film higher in refractive index than the low-refractive index film are alternately stacked. A density of a portion of the low-refractive index film close to an interface between the low-refractive index film and the high-refractive index film is lower than a density of a portion of the low-refractive index film other than the portion close to the interface.

Abstract: A near-infrared cut filter has an optical multilayer provided on at least one main surface of a transparent substrate, in which the optical multilayer is formed of a high-refractive index layer having a refractive index of 2.0 or more, and a low-refractive index layer having a refractive index of 1.6 or less at a wavelength of 500 nm, and the optical multilayer has a repeating structure of (anQH, bnQL, cnQH, dnQL)^n when a QWOT at the wavelength of 500 nm of the high-refractive index layer is set to QH, and a QWOT at the wavelength of 500 nm of the low-refractive index layer is set to QL, in which an average value of the an is not less than 1.5 nor more than 2.5, and a value obtained by averaging average values of the respective bn, cn, and dn is 1.0 or less.

Abstract: An optical filter has a substrate, a refractive index adjusting layer on the substrate, a characteristic improving layer having a stress adjustment function on the refractive index adjusting layer, and an optical multilayer film on the characteristic improving layer, wherein the refractive index adjusting layer is constituted by one to three layers, and the characteristic improving layer is a single-layer film whose physical film thickness is 600 nm or more. The optical filter whose substrate has small warpage and which has a good spectral characteristic is provided.

Abstract: To provide a near infrared cutoff filter capable of suppressing an influence to a captured image when the incidence angle of light to the near infrared cutoff filter is large. The near infrared cutoff filter comprises a substrate to transmit at least light in the visible wavelength region and, on at least one side of the substrate, an infrared reflective layer constituted by a layered film having a high refractive index film H and a low refractive index film L repeatedly laminated, or a layered film having a high refractive index film H, an intermediate refractive index film M and a low refractive index film L? repeatedly laminated, and has light transmittance characteristics such that the difference between the maximum value and the minimum value among the decrease rates in average transmittance in region R, region G and region B, is at most 0.05.

Abstract: A near-infrared cut filter according to the present invention includes a repeated layered structure of a high-refractive index layer, a middle-refractive index layer, and a low-refractive index layer, and includes a transmission band where a mean transmittance is 85% or higher in a wavelength range of 400 nm to 700 nm, and a stopband having a width of 100 nm to 280 nm where a mean transmittance is 10% or lower in a wavelength range of 750 nm to 1100 nm.

Abstract: An optical member has: a transparent substrate; and a dielectric multilayer on the transparent substrate formed by stacking a plurality of unit refractive index layers each formed of a high-refractive index layer having a refractive index of 2 or more and a low-refractive index layer having a refractive index of 1.6 or less. In the optical member, a total number of the unit refractive index layers is 15 or more, and a number of the unit refractive index layers satisfying a condition of nHdH/nLdL?3 is 10 or more, nHdH represents an optical thickness of the high-refractive index layer, and nLdL represents an optical thickness of the low-refractive index layer.

Abstract: There are provided an optical filter excellent in weather resistance and a method for manufacturing an optical filter. The optical filter of the present invention includes a transparent substrate, and an optical multilayer film provided on a surface of the transparent substrate. In the optical multilayer film, a low-refractive index film containing silicon oxide (SiO2) and a high-refractive index film higher in refractive index than the low-refractive index film are alternately stacked. A density of a portion of the low-refractive index film close to an interface between the low-refractive index film and the high-refractive index film is lower than a density of a portion of the low-refractive index film other than the portion close to the interface.

Abstract: Provided is an infrared cut filter including: an infrared absorbing layer of a transparent resin containing an infrared absorber; and a selected wavelength cut layer stacked on the infrared absorbing layer, wherein the following requirements are satisfied. (i) In a spectral transmittance curve for an incident angle of 0°, an average transmittance in a 450-600 nm range is 80% or more, a transmittance in a 700-1200 nm range is 2.0% or less, and D0 represented by the following expression is less than 0.04. D0 (%/nm)=(Tmax·0?Tmin·0)/(?(Tmax·0)??(Tmin·0)) (ii) wherein a spectrum transmittance curve for an incident angle of 30°, an average transmittance in the 450 to 600 nm range is 80% or more, a transmittance in the 700-1200 nm range is 2.0% or less, and D30 represented by the following expression is less than 0.04.

Abstract: To provide a near infrared cutoff filter capable of suppressing an influence to a captured image when the incidence angle of light to the near infrared cutoff filter is large. The near infrared cutoff filter comprises a substrate to transmit at least light in the visible wavelength region and, on at least one side of the substrate, an infrared reflective layer constituted by a layered film having a high refractive index film H and a low refractive index film L repeatedly laminated, or a layered film having a high refractive index film H, an intermediate refractive index film M and a low refractive index film L? repeatedly laminated, and has light transmittance characteristics such that the difference between the maximum value and the minimum value among the decrease rates in average transmittance in region R, region G and region B, is at most 0.05.

Abstract: A near-infrared cut filter according to the present invention includes a repeated layered structure of a high-refractive index layer, a middle-refractive index layer, and a low-refractive index layer, and includes a transmission band where a mean transmittance is 85% or higher in a wavelength range of 400 nm to 700 nm, and a stopband having a width of 100 nm to 280 nm where a mean transmittance is 10% or lower in a wavelength range of 750 nm to 1100 nm.

Abstract: To provide a glass member with an optical multilayer from which film separation of the optical multilayer is suppressed, and a near infrared cut filter glass. A glass member with an optical multilayer, comprising a fluorophosphate glass substrate and an optical multilayer formed on the substrate, wherein an adhesion-strengthening layer consisting of one or more layers, which improves the adhesion of the optical multilayer to the fluorophosphate glass substrate, is formed between the fluorophosphate glass substrate and the optical multilayer; and the optical multilayer is formed by a sputtering method or an ion-beam assisted deposition method, and the adhesion-strengthening layer is formed by a deposition method without using ion-beam assist.

Abstract: An optical member has: a transparent substrate; and a dielectric multilayer on the transparent substrate formed by stacking a plurality of unit refractive index layers each formed of a high-refractive index layer having a refractive index of 2 or more and a low-refractive index layer having a refractive index of 1.6 or less. In the optical member, a total number of the unit refractive index layers is 15 or more, and a number of the unit refractive index layers satisfying a condition of nHdH/nLdL?3 is 10 or more, nHdH represents an optical thickness of the high-refractive index layer, and nLdL represents an optical thickness of the low-refractive index layer.