Nidec Sankyo Corporation

Yosuke Kanzaki

Tadashi Komiyama

Toshio Shirotori

The present invention provides a wide-angle lens capable of obtaining a suitable negative power even when a thickness of a first lens is increased in order to increase strength against impact. The wide-angle lenshas a front group, an aperture, and a rear group. Assuming that a central thickness in an optical axis direction of a first lensis T1 (mm) and a focal length of the entire lens system is f0 (mm), the following conditional expression:1.500≤1/0≤2.000  Conditional expression (1)is satisfied. Therefore, it is possible to suppress the first lensfrom being damaged by impact. In addition, it is possible to prevent the first lensfrom becoming too thick to obtain suitable negative power.

Wide-angle lens

Provided is a lens unit capable of maintaining suitable image formation characteristics even with changes in temperature. The fourth lens outer peripheral face of a fourth lens is not in contact with the inner peripheral face of a second accommodation part. A fifth lens is made of glass, is press fitted and fixed to a resin-made lens holder to form an integrated fifth lens body, and is housed in a lens-barrel. A stepped part formed to engage with a stepped part in the fourth lens is provided in the lens holder outside the fifth lens on the object side of the fifth lens body. A fifth lens body outer peripheral face that is an outermost peripheral face of the fifth lens body comes in contact with the inner peripheral face of the second accommodation part.

Lens unit

Provided is a wide-angle lens, including a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, and a seventh lens, sequentially arranged from an object side. An object-to-image distance of the wide-angle lens is set to d, an entrance pupil diameter of the wide-angle lens is set to HEP, and d/HEP&#x3c;29.000 is satisfied.

Wide-angle lens including seven lenses of&#x2014;+++-+ refractive powers

Provided is a wide-angle lens, including a lens group and a diaphragm. Lenses in the lens group are sequentially arranged from an object side in a manner sandwiching the diaphragm. A maximum half field of view of the wide-angle lens as a whole is set to &#x3c9;, 98&#xb0;&#x3c;&#x3c9;&#x3c;120&#xb0; is satisfied. An effective focal length and an entrance pupil diameter of the wide-angle lens as a whole are set to f and HEP respectively, f/HEP&#x3c;2.3 is satisfied. The lens group includes a first lens that is located closest to the object side and that is a negative lens with a concave surface facing an image side. An effective radius and a radius of curvature of an image side lens surface of the first lens are set to sd12 and R12 respectively, 0.890&#x3c;sd12/R12&#x3c;0.970 is satisfied.

Wide-angle lens including seven lenses of --+++-+ refractive powers

A wide-angle lens is provided. The wide-angle lens includes, sequentially arranged from an object side, a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and an imaging element. The first lens is a negative lens with a convex spherical surface facing the object side and a concave surface facing an image side. The second lens is a negative lens with a concave surface facing the image side. A combined effective focal length of the first lens and the second lens is set to f12 and a maximum image height is set to HOI, &#x2212;1.000&#x3c;f12/HOI&#x3c;&#x2212;0.400 is satisfied.

Wide-angle lens including seven lenses of &#x2212;&#x2212;+++&#x2212;+ refractive powers

A cemented lens may include a first lens and a second lens connected via an adhesive layer. The first lens may include a convex surface facing toward the second lens, and a first flange surrounding an outer circumference of the convex surface. The second lens may include a concave surface connected to the convex surface, and a second flange surrounding an outer circumference of the concave surface. One of the first and second flange may include a projection protruding toward an other of the first and second flange. The other of the first and second flange may include an opposed portion opposed to a side surface of the projection Ga is a distance between the convex surface and the concave surface, and Gb is a distance between the side surface and the opposed portion, and the following expression: Gb&#x3c;Ga may be satisfied.

Lens unit and cemented lens

A wide-angle lens includes a front group, an aperture, a rear group, and an infrared cut filter. The front group includes a first lens and a second lens arranged in order from a side closest to an object to an image side. In the wide-angle lens, an anti-reflection layer having a reflectance of 1.5% or less in a wavelength range from nm to 850 nm is provided on a lens surface of the first lens on the image side to suppress an occurrence of a ghost caused by light passing through a peripheral portion of the lens surface. Therefore, even if a film forming the anti-reflection layer is thinner than an appropriate value at the peripheral portion of the lens surface, the anti-reflection layer appropriately prevents reflection of light in a long wavelength range.

A wide-angle lens () includes a front group (), an aperture (), and a rear group (). The front group () includes a first lens () and a second lens () arranged from a side (La) closest to an object to an image side (Lb). In such a wide-angle lens, to suppress an occurrence of a ghost caused by multiple reflection between a lens surface () of the first lens () on the image side (Lb) and a lens surface () of the second lens () on the object side (La), the sag amount Sag21 (mm) and the diameter D21 (mm) of the lens surface () satisfy the following conditional expression: 0&#x3c;|Sag21/(D21/2)|&#x3c;0.125.

Wide-angle lens capable of suppressing multiple reflection between the first lens and the second lens

A wide-angle lens () includes a front group (), an aperture (), and a rear group (). The front group () includes a first lens (), a second lens (), and a third lens () arranged in order from a side (La) closest to an object to an image side (Lb). In such a wide-angle lens, to suppress an occurrence of a ghost caused by multiple reflection between a lens surface () of the second lens () on the image side (Lb) and a lens surface () of the third lens () on the object side (La), the sag amount Sag31 (mm) and the diameter D31 (mm) of the lens surface () satisfy the following conditional expression: 0&#x3c;1Sag31/(D31/2)&#x3c;0.125.

Wide-angle lens capable of suppressing multiple reflection between the second lens and the third lens

A manufacturing method of a plastic lens formed by using a metal mold having a fixed mold and a movable mold. The plastic lens comprises a flange part surrounding a lens face, and an image side face of the flange part comprises a black coating part and an outer peripheral part. The manufacturing method may include a molding process in which the plastic lens is molded by using the fixed mold for molding an object side lens face and the movable mold for molding an image side lens face and the flange part, a mold opening process in which the metal mold is opened by moving the movable mold, and a pushing-out process in which the outer peripheral part is pushed out by an ejector pin disposed in the movable mold when the mold opening process is performed or, after the mold opening process has been performed.

Manufacturing method of plastic lens

Provided is a lens unit. A second lens is provided with a flange surface section that surrounds a lens surface. An image-side flange surface has an image-side flange surface inner-circumferential section which is shaped like a ring-shaped groove, and also has a ring-shaped image-side flange surface outer-circumferential section formed to the outside of the inner-circumferential section. The image-side flange surface inner-outer circumferential section is coated with black ink. The image-side flange surface outer-circumferential section is provided with boss-shaped positioning surface at six equidistant locations along the outer circumference. Ejector pin contact sections are formed between adjacent positioning surface, and said contact sections contact the ejector pins at the time of separation from the mold during resin molding.

An imaging lens system may include a first lens; a second lens; a third lens; a diaphragm; a fourth lens; a fifth lens; a sixth lens; and a seventh lens. The first lens may be a positive meniscus lens. The second lens may be a negative meniscus lens. The third lens may be a meniscus lens comprising. The fourth lens may be a positive lens. The fifth lens may be a positive lens. The sixth lens may be a negative lens comprising a sixth lens concave surface facing the image side. The seventh lens may be a positive lens comprising a seventh lens convex surface facing the object side. The fifth lens may be a glass lens. The second, third, fourth, sixth and seventh lenses may be plastic lenses. The sixth lens concave surface may be joined to the seventh lens convex surface with an adhesive.

Imaging lens system

A wide-angle lensincludes a first lens, a second lens, a third lens, a diaphragm, a fourth lens, and a fifth lens. The first lensis a negative meniscus lens whose lens surface on an image side Lb is a concave curved surface. The second lensis a negative lens whose lens surface on the image side Lb is a concave curved surface and whose lens surface on the object side La is convex curved surface. The third lensis a positive lens whose lens surface on the image side Lb is a convex curved surface. The fourth lensis a negative lens whose lens surface on the image side Lb is a concave curved surface. The fifth lensis a biconvex lens. A refractive index n1 of the first lenssatisfies a conditional expression.

A wide angle lens includes a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens and a seventh lens which are disposed in order from an object side. The first, second, third and sixth lenses are negative meniscus lenses, and the fourth, fifth and seventh lenses are positive lenses. The fifth lens is a glass lens, and the second, third, fourth, sixth and seventh lenses are plastic lenses. The sixth lens and the seventh lens constitute a cemented lens. When a center curvature radius on an image side face of the fifth lens is R52 and a focal length of an entire wide angle lens is f0, the center curvature radius R52 and the focal length f0 satisfy the following conditional expression:2&#xd7;0&#x2264;|52|&#x2264;5&#xd7;0.

Wide angle lens

An in-vehicle camera lens unit having stable temperature characteristics even when lenses are mounted in a resin holder is provided. With an in-vehicle camera lens unit, a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, and a sixth lens, which are disposed in this order from an object side to an image side, are held in a resin holder. The first lens, the second lens, the fifth lens, and the sixth lens are glass lenses, and of the third lens and the fourth lens disposed on both sides of the diaphragm, the third lens, which is a meniscus lens, is a plastic lens, and the fourth lens, which is a double convex lens, is a glass lens.

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Nagano, Japan

Yosuke Kanzaki