Abstract: A microscope includes an optical element provided with an anti-reflection film applied thereto. The anti-reflection film has the following layered structure: having first to sixth layers of films, in order from the surface of the optical element, formed of a high-refractive-index material for each of the first, third and fifth layers, a low-refractive-index material or a middle-refractive-index material for each of the second and fourth layers, and a low-refractive-index material for the sixth layer, with a range of the optical film-thickness nd of each layer in reference to the design wavelength ? being “(0.13˜0.35)×?/4” for the first layer, “(0.18˜0.75)×?/4” for the second layer, “(0.28˜2.31)×?/4” for the third layer, “(0.26˜0.92)×60 /4” for the fourth layer, “(0.20˜0.37)×?/4” for the fifth layer, and “(1.09˜1.18)×?/4” for the sixth layer.

Abstract: A microscope includes an optical element provided with an anti-reflection film applied thereto. The anti-reflection film has the following layered structure: having first to sixth layers of films, in order from the surface of the optical element, formed of a high-refractive-index material for each of the first, third and fifth layers, a low-refractive-index material or a middle-refractive-index material for each of the second and fourth layers, and a low-refractive-index material for the sixth layer, with a range of the optical film-thickness nd of each layer in reference to the design wavelength ? being “(0.13˜0.35)×?/4” for the first layer, “(0.18˜0.75)×?/4” for the second layer, “(0.28˜2.31)×?/4” for the third layer, “(0.26˜0.92)×?/4” for the fourth layer, “(0.20˜0.37)×?/4” for the fifth layer, and “(1.09˜1.18)×?/4” for the sixth layer.

Abstract: A fluorescence observing apparatus has an excitation filter unit for transmitting only exciting light with particular wavelengths, of illuminating light, and an absorption filter unit for transmitting only fluorescent light produced from a specimen by irradiating the specimen with the exciting light to block the exciting light. In this case, the space between the half-value wavelength on the long-wavelength side of the excitation filter unit and the half-value wavelength on the short-wavelength side of the absorption filter unit is in the range of 6–12 nm, and variations in the half-value wavelengths of the excitation filter unit and the absorption filter unit where humidity is changed from 10% to 95% are within 0.5 nm. Whereby, faint fluorescent light is efficiently taken out and the observation can be made.

Abstract: An optical filter is provided with a thin film having: a first laminated portion that is constructed by alternately laminating low refractive index layers that have a relatively low refractive index with high refractive index layers that have a relatively high refractive index, and in which the refractive index of the high refractive index layers gradually increases from the substrate side; a second laminated portion in which the refractive indices of the high refractive index layers are equal to or higher than the highest refractive index from among the high refractive index layers constituting the first laminated portion; and a third laminated portion in which the refractive indices of the high refractive index layers gradually decrease from the second laminated portion side.

Abstract: A microscope includes an optical element provided with an anti-reflection film applied thereto. The anti-reflection film has the following layered structure: having first to sixth layers of films, in order from the surface of the optical element, formed of a high-refractive-index material for each of the first, third and fifth layers, a low-refractive-index material or a middle-refractive-index material for each of the second and fourth layers, and a low-refractive-index material for the sixth layer, with a range of the optical film-thickness nd of each layer in reference to the design wavelength ? being “(0.13˜0.35)×?/4” for the first layer, “(0.18˜0.75)×?/4” for the second layer, “(0.28˜2.31)×?/4” for the third layer, “(0.26˜0.92)×?/4” for the fourth layer, “(0.20˜0.37)×?/4” for the fifth layer, and “(1.09˜1.18)×?/4” for the sixth layer.

Abstract: This optical filter provides a substrate and thin films. The thin films comprise an outermost layer portion and a refractive index varying portion. The refractive index varying portion is formed by laminating alternately towards the substrate a low refractive index layer having a refractive index that is higher than that of air and a high refractive index layer having a refractive index that is higher than the low refractive index layer. The outermost layer portion comprises an outermost low refractive index layer having a refractive index that is higher than that of air, a first outermost high refractive index layer having a refractive index that is higher than that of the outermost low refractive index layer, and a second outermost high refractive index layer having a refractive index that is higher than that of the first outermost high refractive index layer.

Abstract: A fluorescence observing apparatus has an excitation filter unit for transmitting only exciting light with particular wavelengths, of illuminating light, and an absorption filter unit for transmitting only fluorescent light produced from a specimen by irradiating the specimen with the exciting light to block the exciting light. In this case, the space between the half-value wavelength on the long-wavelength side of the excitation filter unit and the half-value wavelength on the short-wavelength side of the absorption filter unit is in the range of 6-12 nm, and variations in the half-value wavelengths of the excitation filter unit and the absorption filter unit where humidity is changed from 10% to 95% are within 0.5 nm. Whereby, faint fluorescent light is efficiently taken out and the observation can be made.

Abstract: In an optical filter, a thin film is formed by laminating low refractive index layers alternatingly from a substrate side with high refractive index layers. The thin film is provided with first, second, and third laminated portions. In the first laminated portion, the refractive indices of the high refractive index layers become gradually higher. In the second laminated portion, the refractive indices of the high refractive index layers are substantially equal to the highest refractive index of the high refractive index layers constituting the first laminated portion. In the third laminated portion, the refractive indices of the high refractive index layers become gradually lower, and the refractive indices of the low refractive index layers are substantially equal to the lowest refractive index of the low refractive index layers constituting the second laminated portion.

Abstract: An optical filter is provided with a thin film having: a first laminated portion that is constructed by alternately laminating low refractive index layers that have a relatively low refractive index with high refractive index layers that have a relatively high refractive index, and in which the refractive index of the high refractive index layers gradually increases from the substrate side; a second laminated portion in which the refractive indices of the high refractive index layers are equal to or higher than the highest refractive index from among the high refractive index layers constituting the first laminated portion; and a third laminated portion in which the refractive indices of the high refractive index layers gradually decrease from the second laminated portion side.

Abstract: The optical measuring device of film thickness consists of a spectral reflectance measuring device and a film thickness deciding device. The film thickness deciding device comprises a reflectance operating device, an evaluation function operating device, a global optimization device, a local optimization device, and settlement judging devices added to the global optimization device and the local optimization device respectively. A data selecting device may be interposed between the spectral reflectance measuring device and the film thickness deciding device. The optical measuring device of film thickness is capable of measuring thickness of individual layers of a multi-layer film simultaneously, speedily and accurately.