JP2015200805A5

JP2015200805A5 - Optical filter, ND filter, light quantity diaphragm device, and imaging device

Info

Publication number: JP2015200805A5
Application number: JP2014079905A
Authority: JP
Filing date: 2014-04-09
Publication date: 2017-04-20
Anticipated expiration: 2034-04-09

Description

上記した課題を解決するために、本発明に係る光学フィルタの技術的特徴は、透明基板の表面に可視光波長以下のピッチと高さの複数の突起部を有する微細凹凸周期構造を形成し、前記複数の突起部の最頂部の屈折率は、前記透明基板の屈折率よりも小さく、前記複数の突起部は前記透明基板側から前記最頂部側に向かって屈折率が連続的に減少する特性を有していることを特徴とする。
また、本発明に係るＮＤフィルタの技術的特徴は、透透明基板の表面に可視光波長以下のピッチと高さの複数の突起部を有する微細凹凸周期構造を設け、前記透明基板の裏面上に、ＮＤ膜を設け、前記複数の突起部の最頂部の屈折率は、前記透明基板の屈折率よりも小さく、前記複数の突起部は前記ＮＤ膜側から前記最頂部側に向かって屈折率が連続的に減少する特性を有していることを特徴とする。 In order to solve the above-described problems, the technical feature of the optical filter according to the present invention is to form a fine uneven periodic structure having a plurality of protrusions having a pitch and height below the visible light wavelength on the surface of the transparent substrate, refractive index of the topmost of said plurality of protrusions is smaller than the refractive index of the transparent substrate, the plurality of protrusions decreases from the transparent substrate side continuously refractive index toward the topmost portion side characteristic It is characterized by having .
The technical feature of the ND filter according to the present invention is that the surface of the transparent substrate is provided with a fine uneven periodic structure having a plurality of protrusions having a pitch and height less than or equal to the visible light wavelength, on the back surface of the transparent substrate. , An ND film is provided, and the refractive index at the top of the plurality of protrusions is smaller than the refractive index of the transparent substrate, and the plurality of protrusions has a refractive index from the ND film side toward the topmost side. It has a characteristic of continuously decreasing.

Claims

Form a fine irregular periodic structure having a plurality of protrusions with a pitch and height below the visible light wavelength on the surface of the transparent substrate,
The refractive index of the top of the plurality of protrusions is smaller than the refractive index of the transparent substrate,
Wherein the plurality of protrusions optical filter, characterized in that it has a characteristic that the refractive index toward the topmost side from the transparent substrate side is reduced continuously.

The fine irregularities on the periodic structure or the back surface of the transparent substrate, the optical filter according to claim 1, the inorganic hard film is characterized in that it is deposited.

The optical filter according to claim 2, wherein the inorganic hard film includes a light absorption layer made of a metal or a metal oxide and a dielectric layer.

A light quantity diaphragm device comprising the optical filter according to any one of claims 1 to 3.

An imaging apparatus comprising: an optical system; a light quantity diaphragm device according to claim 4 that limits an amount of light that passes through the optical system; and a solid-state imaging device that receives an image formed by the optical system.

  Provide a fine irregular periodic structure having a plurality of protrusions with a pitch and height below the visible light wavelength on the surface of the transparent substrate,
  On the back surface of the transparent substrate, an ND film is provided,
  The refractive index of the top of the plurality of protrusions is smaller than the refractive index of the transparent substrate,
  The ND filter, wherein the plurality of protrusions have a characteristic that a refractive index continuously decreases from the ND film side toward the topmost side.

An imaging device comprising the ND filter according to claim 6.