Abstract: Provided are an organic-inorganic composite resin composition and an organic-inorganic composite resin material made of a cured product thereof, containing at least an organic compound having a polymerizable functional group, metal oxide fine particles, and a polymerization initiator. The cured product obtained by curing the organic-inorganic composite resin composition through application of an active energy has a refractive index nd of 1.61 or more and 1.65 or less, Abbe's number ?d of 13 or more and 20 or less, and an anomalous dispersion characteristic ?g,F of 0.42 or more and 0.54 or less. Further provided is an optical element comprising a transparent substrate and the organic-inorganic composite resin material formed on the transparent substrate.

Abstract: An optical material includes a cured product of a resin composition at least containing indium tin oxide (ITO) fine particles and an optical resin and provides a minimum refractive index (which is a value that satisfies the relationship of dn/d?=0 and d2n/d?2>0 where n represents the refractive index, ? represents the wavelength of light, dn/d? represents the first-order differentiated refractive index with respect to the wavelength of the light, and d2n/d?2 represents the second-order differentiated refractive index with respect to the wavelength of the light) within a wavelength range of 1600 nm or more and 1800 nm or less. The optical material has optical characteristics in which absorbance in the visible-light region is low and the second-order dispersion is low.

Abstract: A multi-layered diffraction optical element, comprises a transparent substrate, a first layer having a diffraction grating shape at least on one face and comprised of a relatively high refractive index and low dispersion material, and a second layer having a diffraction grating shape at least on one face and comprised of a relatively low refractive index and high dispersion material, wherein the first and second layers are laminated on the transparent substrate so that the respective diffraction grating shapes are mutually opposed to each other with no space therebetween, and, the first layer is comprised of a first organic resin including a first inorganic fine particle, and the second layer is comprised of a second organic resin including a second inorganic fine particle different from the first inorganic fine particle.

Abstract: A multi-layered diffraction optical element, comprises a transparent substrate, a first layer having a diffraction grating shape at least on one face and comprised of a relatively high refractive index and low dispersion material, and a second layer having a diffraction grating shape at least on one face and comprised of a relatively low refractive index and high dispersion material, wherein the first and second layers are laminated on the transparent substrate so that the respective diffraction grating shapes are mutually opposed to each other with no space therebetween, and, the first layer is comprised of a first organic resin including a first inorganic fine particle, and the second layer is comprised of a second organic resin including a second inorganic fine particle different from the first inorganic fine particle.

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.

Abstract: An optical material is a mixture of materials comprising a first material having a refractive index of not more than 1.45 for the d-line and a second material having an Abbe's number, indicating wavelength dispersion in the visible region, of not more than 25. A relation between the refractive index for the d-line (nd) and the Abbe's number (?d) is defined as follows: nd??6.667×10?3?d+1.70.

Abstract: To provide an optical element in which the diffraction efficiency in each use wavelength region within the entire visible region is preferable, and light beams of a specific order (design order) are sufficiently concentrated in the entire use wavelength region, by using an optical material in which the relationship between a refraction index nd and an Abbe number ?d with respect to a “d” line is nd>?6.667×10?3?d+1.70 and the Abbe number ?d satisfies ?d?16.

Abstract: An optical element of which diffraction efficiency hardly varies with wavelength is provided by using an optical material satisfying the conditions that nd>?6.667×10?3?d+1.70 and ?g,F??2×10?3?d+0.59 where nd is a refractive index at d-line, ?d is an Abbe number at the d-line, and ?g,F is a second order dispersion at d-line, whereby diffraction efficiency is improved in any working visible wavelength region and more precise chromatic aberration correction is obtained.

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.

Abstract: An optical element of which diffraction efficiency hardly varies with wavelength is provided by using an optical material satisfying the conditions that nd>?6.667×10?3?d+1.70 and ?g,F??2×10?3?d+0.59 where nd is a refractive index at d-line, ?d is an Abbe number at the d-line, and ?g,F is a second order dispersion at d-line, whereby diffraction efficiency is improved in any working visible wavelength region and more precise chromatic aberration correction is obtained.

Abstract: In a fog prevention and antireflection optical element including a first water absorption layer containing a water-absorbing polymer as its main component, a high refractive layer, and a second water absorption layer which are formed on a base in this order, an inorganic material (nd>1.70) is mixed in the water-absorbing polymer of the first water absorption layer, whereby the difference in refractive index with respect to the optical element is decreased.

Abstract: An optical element of which diffraction efficiency hardly varies with wavelength is provided by using an optical material satisfying the conditions that nd>?6.667×10?3vd+1.70 and ?g,F??2×10?3?d+0.59 where nd is a refractive index at d-line, ?d is an Abbe number at the d-line, and ?g,F is a second order dispersion at d-line, whereby diffraction efficiency is improved in any working visible wavelength region and more precise chromatic aberration correction is obtained.

Abstract: In order to provide an optical element which prevents fogging of a surface and has an antireflection characteristic and morphological stability, an optical element of the present invention includes: a substrate; and a first water absorption layer containing a water-absorbing polymer and inorganic particles, a high refractive layer, and a second water absorption layer which are formed on a substrate in this order, in which the water absorption layer is made of a material containing a mixture of a water-absorbing polymer and an inorganic substance.

Abstract: In order to provide an optical element which prevents fogging of a surface and has an antireflection characteristic and morphological stability, an optical element of the present invention includes: a substrate; and a first water absorption layer containing a water-absorbing polymer and inorganic particles, a high refractive layer, and a second water absorption layer which are formed on a substrate in this order, in which the water absorption layer is made of a material containing a mixture of a water-absorbing polymer and an inorganic substance.

Abstract: An optical material is a mixture of materials comprising a first material having a refractive index of not more than 1.45 for the d-line and a second material having an Abbe's number, indicating wavelength dispersion in the visible region, of not more than 25. A relation between the refractive index for the d-line (nd) and the Abbe's number (&ngr;d) is defined as follows: nd≦−6.667×10−3&ngr;d+1.70.

Abstract: An optical material is a mixture of materials comprising a first material having a refractive index of not more than 1.45 for the d-line and a second material having an Abbe's number, indicating wavelength dispersion in the visible region, of not more than 25.

Abstract: An optical element of which diffraction efficiency hardly varies with wavelength is provided by using an optical material satisfying the conditions that nd>−6.667×10−3vd+1.70 and &thgr;g,F≦−2×10−3vd+0.59 where nd is a refractive index at d-line, vd is an Abbe number at the d-line, and &thgr;g,F is a second order dispersion at d-line, whereby diffraction efficiency is improved in any working visible wavelength region and more precise chromatic aberration correction is obtained.

Abstract: To provide an optical element in which the diffraction efficiency in each use wavelength region within the entire visible region is preferable, and light beams of a specific order (design order) are sufficiently concentrated in the entire use wavelength region, by using an optical material in which the relationship between a refraction index nd and an Abbe number &ngr;d with respect to a “d” line is nd>−6.667×10−3&ngr;d+1.70 and the Abbe number &ngr;d satisfies &ngr;d≦16.

Abstract: When a light beam is incident on a diffraction optical element at a large incidence angle, the light beam is shaded to generate flare or ghost, thereby increasing chromatic aberration. To solve this, polyvinylcarbazole is used as an optical element material to form a diffraction optical element in a mold by means of heat molding, solvent evaporation, thermal polymerization, photopolymerization, and the like. In particular, for the thermal polymerization and the photopolymerization, N-vinylcarbazole, i.e., fluid monomer, is supplied into a mold and is then polymerized. Even if the diffractive structure is complicated and fine, it can be easily shaped. An optical material to be used comprises polyvinylcarbazole added with a thermal initiator, a photoinitiator, a compound having two or more unsaturated ethylene groups with a photoinitiator, and the like.

Abstract: In order to provide an optical element which prevents fogging of a surface and has antireflection characteristic and morphological stability, an optical element of the present invention includes: a substrate; and a first water absorption layer containing a water-absorbing polymer and inorganic particles, a high refractive layer, and a second water absorption layer which are formed on a substrate in this order, in which the water absorption layer is made of a material containing a mixture of a water-absorbing polymer and an inorganic substance.