Optical filter, optical device, electronic device and anti-reflection composite
AssigneeCanon Denshi Kabushiki Kaisha
InventorsMasayuki Uchiyama, Michio Yanagi
Life of this patent
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Abstract
There is provided an optical filter or an anti-reflection structure with lower reflection in comparison with the conventional ones by comprising a gradient refractive index thin film 12 with continuous, periodic refractive index change in the film thickness direction and a fine periodic structure 151 lowering reflection, wherein the refractive index of the gradient refractive index thin film 12 in its thickness direction on the substrate side changes so as to become close to that of the substrate, while on the fine periodic structure 111 changes so as to become close to that of the fine periodic structure 151. The optical filter can be used in an optical device or an electronic device display.
Claims15
An optical filter comprising:
- a light-transmitting and transparent substrate serving as (a) a part of the optical filter and (b) a target for film forming,
- a gradient refractive index thin film with refractive index change in the film thickness direction formed on the substrate;
- and
- a fine structure having a pitch shorter than the wavelength of visible light formed on the gradient refractive index thin film,
- wherein the fine structure is formed by a material having a refractive index different from the refractive index of the substrate,
- wherein the gradient refractive index thin film is formed by a film having no interface, which film is formed by a plurality of film-forming materials, the mixing ratio of which is changed in the film thickness direction, and
- wherein the refractive index change is continuous in the film thickness direction, on the substrate side, so as to be close to the refractive index of the substrate, and, on the fine structure side, so as to be close to the refractive index of the fine structure.
An anti-reflection composite comprising:
- a gradient refractive index thin film with refractive index change in its thickness direction formed on a light-transmitting and transparent substrate, the substrate serving as (a) a part of an optical filter and (b) a target for film forming;
- an adhesive layer to stick fine structural parts on the gradient refractive index thin film;
- and
- fine structural parts arranged at a pitch shorter than the wavelength of visible light, the fine structural parts being formed on the gradient refractive index thin film through the adhesive layer,
- wherein the gradient refractive index thin film is formed by a film having no interface, which film is formed by a plurality of film-forming materials, the mixing ratio of which is changed in the film thickness direction, and
- wherein the refractive index change is continuous in the film thickness direction, on the substrate side, so as to be close to the refractive index of the substrate and, on the fine structural parts side, so as to be close to the refractive index of the fine structural parts.
Dependencies are inferred from the claim text.