An optical filter (1) in which, in a transmission spectrum of the optical filter, when: a minimum value of transmissivity for a wavelength range of from 400 nm to 450 nm, inclusive, is defined as first minimum value MIN1; a minimum value of transmissivity for a wavelength range of from 525 nm to 595 nm, inclusive, is defined as second minimum value MIN2; a maximum value of transmissivity for a wavelength range of from 450 nm to 525 nm, inclusive, is defined as first maximum value MAX1; and a maximum value of transmissivity for a wavelength range of from 595 nm to 600 nm, inclusive, is defined as second maximum value MAX2, first minimum value MAX1 and second minimum value MIN1 are each at most ½ a smaller one of first maximum value MAX1 and second maximum value MAX2.

Provided is a near infrared absorbing glass excellent in each of weather resistance, resistance to denitrification, and optical properties even if not containing fluorine. A near infrared absorbing glass containing, in % by mass, 25 to 60% P.sub.2O.sub.5, 2 to 19% Al.sub.2O.sub.3, 10 to 45% RO (where R is at least one selected from Mg, Ca, Sr, and Ba), 0 to 13% ZnO, 12% to 20% (exclusive of 12% and 20%) K.sub.2O, 0 to 12% Na.sub.2O, and 0.3 to 20% CuO.

The present invention relates to an optical article, and an optical filter and an imaging device including the same. The optical article comprises: a near-infrared absorption glass substrate including a divalent copper ion as a chromatic ingredient; and a pigment dispersion layer formed on one surface or both surfaces of the near-infrared absorption glass substrate and having a near-infrared absorption pigment and an ultraviolet absorption pigment dispersed across the resin matrix thereof. Provided with a first and a second transmission cut-off region, the optical article has the advantage of allowing the fabrication of an excellent near-infrared cut-off filter that can effectively block light in near-infrared and ultraviolet bands and does not permit a difference in color sense with the change of incident angles.

A glass ceramic for an optical filter and an optical filter are obtained that have both thermal expansion characteristics for preventing refractive index fluctuations at a usage temperature of a filter member and mechanical characteristics considering durability, and further have excellent workability.

An internal transmittance of the glass ceramic for an optical filter is 0.970 or more with respect to light having a wavelength of 1550 nm when a thickness of the glass ceramic is 1 mm. The glass ceramic includes, by mass % in terms of oxide, 40.0% to 70.0% of a SiO.sub.2 component, 11.0% to 25.0% of an Al.sub.2O.sub.3 component, 5.0% to 19.0% of a Na.sub.2O component, 0% to 9.0% of a K.sub.2O component, 1.0% to 18.0% of one or more components selected from a MgO component and a ZnO component, 0% to 3.0% of a CaO component, and 0.5% to 12.0% of a TiO.sub.2 component.

The disclosure relates in general to illuminated panels resembling windows, and more particularly, to a system containing a light source, a diffuser and a panel combined in such a fashion as to resemble a window, skylight or curtain wall.

A near-infrared absorbing material fine particle dispersion, a near-infrared absorber laminate, and a laminated structure for near-infrared absorption can exhibit higher near-infrared absorption property, compared to near-infrared fine particle dispersions, near-infrared absorber laminates, and laminated structures for near-infrared absorption, containing tungsten oxides or composite tungsten oxides according to the conventional art. Also, a near-infrared absorbing material fine particle dispersion in which composite tungsten oxide fine particles, each particle containing a hexagonal crystal structure, and a polymer compound with maleic anhydride introduced therein are contained in the polypropylene resin, and the near-infrared absorber laminate and the laminated structure for near-infrared absorption using the dispersion.

An optical filtering apparatus fashioned as a pair of glasses; that enhance the contrast and visibility of objects with specified colors. A set of distinct attenuations are combined to produce an optical filter that promotes a specified color.

In the present application, a sharp visible light transmission band can be obtained while efficiently and accurately blocking ultraviolet light near the short-wavelength visible light region and infrared light near the long-wavelength visible light region, and the ripple phenomenon can be minimized regardless of the incident angle. It is possible to provide an optical filter capable of obtaining high visible light transmittance while securing the above characteristics even in the case where a near-infrared absorption glass is used as a substrate.

A light diffusion member includes a substrate that has optical transparency, a light diffusion portion that is formed with a prescribed height on one surface of the substrate, a light shielding layer that is formed with a thickness less than the height of the light diffusion portion in another region of the one surface of the substrate than the light diffusion portion, and an antiglare layer that is formed on the other surface of the substrate. The light diffusion portion includes a light emission end surface that contacts with the substrate, a light incident end surface that faces the light emission end surface and has a larger area than an area of the light emission end surface, and a side surface that is formed between the light emission end surface and the light incident end surface, and the antiglare layer includes a binder layer and plural light diffusion particles that are dispersedly arranged in the binder layer.

An infrared optical filter may include a glass ceramic layer, a multilayer oxide thin film formed on a first surface of the glass ceramic layer, and a low reflectivity coating layer formed on a second surface of the glass ceramic layer.