Optical element and production method of the same
Disclosed is an optical element for use in an optical apparatus having a light source which emits a light flux with a wavelength λ (350 nm≦λ≦450 nm), the optical element containing: a molded portion formed by molding a resin; and one or a plurality of anti-reflection layers formed on the molded portion, wherein at least one of the anti-reflection layers is made of Si x O y ; and an elemental ratio r (r=y/x) designating an ratio of O to Si in the molecule of Si x O y satisfies a requirement represented by Formula (1): 1.40≦r≦1.80.
1. An optical element for use in an optical apparatus having a light source which emits a light flux with a wavelength λ(350 nm≦λ≦450 nm), the optical element comprising: a molded portion formed by molding resin; one or a plurality of anti-reflection layers formed on the molded portion, wherein at least one of the anti-reflection layers is in direct contact with the molded portion and is made of Si x O y , wherein the one or a plurality of anti-reflection layers is/are disposed on only the side through which light exits or on both sides of the molded portion; and an elemental ratio r (r=y/x) designating a ratio of O to Si in the molecule of Si x O y satisfies a requirement represented by Formula (1): Formula (1) 1.40≦r≦1.75, wherein the optical element receives the light flux with the wavelength λ, and wherein the optical element has an image-side numerical aperture of 0.7 or more.
2. The optical element described in claim 1 , wherein the resin to form the molded portion is a cyclic olefin resin.