Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

Abstract: A method for manufacturing an optical element including: a surface including a plurality of grooves arranged concentrically. Each of the grooves includes a bottom surface with a predetermined width, a side surface, and a curved surface with a predetermined curvature radius. The bottom surface extends in a radius direction of the grooves. The curved surface connects the bottom surface and the side surface.

Abstract: Provided is an objective optical element which can appropriately correct degradation from spherical aberration upon fluctuation of a light source wavelength while maintaining light use efficiency, just by changing the magnification of the objective optical element, and which can record/reproduce information to/from different optical discs. Also provided is an optical pickup device using the objective optical element. When a light flux having two different wavelengths ?11, ?12 (wherein ?11<?12 and ?12??11=5 nm) within a range of wavelength ?1 is introduced to the objective optical element to measure the wavefront aberration, the following third order and fifth order spherical aberrations in unit of ?rms are obtained: SA3(?11), SA5(?11), SA3(?12), SA5(?12). If ?SA3=|SA3(?12)?SA3(?11)|, ?SA5=|SA5(?12)?SA5(?11)|, the following expression is satisfied: 0.

Abstract: Disclosed is an optical element for use in an optical apparatus having a light source which emits a light flux with a wavelength ? (350 nm???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 SixOy; and an elemental ratio r (r=y/x) designating an ratio of O to Si in the molecule of SixOy satisfies a requirement represented by Formula (1): 1.40?r?1.80.

Abstract: An image pickup lens includes: a first lens with a positive power, including a convex surface facing the object side; an aperture stop; a second lens with a negative power, including a concave surface facing the image side; a third lens with a positive or negative power; a fourth lens with a positive power, including a convex surface facing the image side; and a fifth lens with a negative power, including a concave surface facing the image side. The surface of the fifth lens facing the image side is an aspheric surface and includes an inflection point. The image pickup lens satisfies the predetermined condition relating to a focal length of the first lens.