Nidec Copal Corporation

Yasuhiko Abe

Kazuya Murakami

Hotaka Takeuchi

Youhei Nagai

Yoichi Ishikawa

A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power. The first, second, and third lens units are arranged in that order from an object side to an image plane side of the zoom lens. The first lens unit includes a first lens having a negative refractive power, the second lens unit includes a second lens having a positive refractive power and a third lens having a negative refractive power, and the third lens unit includes a fourth lens having a positive refractive power. During zooming from a wide-angle end to a telephoto end, the first lens unit is fixed, and the second lens unit and the third lens unit are moved.

Zoom lens

A zoom lens is equipped with: a first lens group having an overall negative refractive power and a second lens group having an overall positive refractive power in sequence from the object side to the image plane side. Zoom magnification is changed from a wide-angle end to a telephoto end by moving the first lens group to the image plane side and then reversing the motion to the object side while the second lens group is moved to the object side. The condition (1) 0.90&#x3c;=(DG+DG)/fw&#x3c;=2.30 and the condition (2) 0.5&#x3c;=|fG|/fG&#x3c;=1.6 are met, where DGis the thickness of the first lens group; DGis the thickness of the second lens group; fw is the focal length of the lens system at the wide-angle and; fGis the focal length of the first lens group; and fGis the focal length of the second lens group. With above structure, the power arrangements for the first and second lens groups are set appropriately providing a zoom magnification ratio of approximately 3&#xd7; beside making the design of the zoon lens compact and thin.

An imaging lens includes, in sequence from the object side to the image plane side: a first lens with a convex object side surface and having a positive overall index of refraction; an aperture stop having a predetermined diameter; a second lens with a convex object side surface and having an overall positive index of refraction; and a third lens with a concave object side surface and an overall negative index of refraction. At least one surface of the first lens is formed as an aspherical surface. Both surfaces of the third lens are formed as aspherical surfaces, with the image side surface having an inflection point at which the curvature of the surface changes within the effective diameter range. The imaging lens provides superior optical characteristics and is compact and suited for use in mobile cameras installed in portable telephones, PDAs, and the like.

Imaging lens

The present invention includes, from an object side to an image-plane side: an aperture stop with a predetermined diameter, a first lens with a positive refractive power having a convex surface on the object side, a second lens with a positive refractive power having a concave surface on the object side, and a third lens with a negative refractive power having a convex surface on the object side. The second and third lenses have aspherical surfaces on their object-side and image-plane-side surfaces. The third lens is formed with an inflection point where the curvature orientation changes within the effective diameter range of the aspherical surface on the image-plane side. An appropriate back focus is maintained while the total length of the lens system is reduced. A compact, thin, high-performance design is achieved, which effectively corrects various aberrations, especially astigmatism and distortion, and is suited for digital cameras using high-density solid-state imaging elements of one million pixels or more.

The present invention includes, from the object side to the image plane side, an aperture stop with a predetermined diameter, a first lens with a positive refractive power and a bi-convex shape with convex surfaces facing the object side and the image plane side, a second lens being formed as a meniscus shape with a concave surface facing the object side having a negative refractive power, and a third lens being formed as a meniscus shape with a convex surface facing the object side having a positive refractive power. By having a positive refractive power for the first lens and third lens and a negative refractive power for the second lens, a suitable back focus can be maintained while reducing the total length of the lens system. The imaging lens is thin and compact and has superior optical properties suited for mobile cameras mounted in portable telephones and PDAs.

A photographing lens includes an aperture stop having a predetermined aperture, a first lens having a positive refractive power and a convex surface facing the object side, a second lens having a positive refractive power and aspherical surfaces on both sides, the object-side aspherical surface being concave, and a third lens having a negative refractive power and aspherical surfaces on both sides, the object side surface being convex. The aperture stop and the first, second, and third lenses are arranged in order from the object side toward the image-plane side. With such a three-unit, three element lens configuration, a proper back focus is ensured, aberrations are properly corrected, and the total lens length and thickness of the photographing lens are reduced. The photographing lens can be suitably applied to high-resolution image pickup devices with a million pixels or more.

Photographing lens

The photographing lens of the present invention includes, starting from the object side: an aperture stop having a predetermined aperture; a first lens group having a positive overall refractive power; a second lens group having a positive overall refractive power; and a third lens group having a positive overall refractive power. The first lens group is a cemented lens with, from the object side, a first lens with a positive refractive power and a second lens with a negative refractive power. The second lens group includes a third lens with a positive refractive power and at least one aspherical surface. The third lens group includes a fourth lens with a positive refractive power and at least one aspherical surface. The present invention provides a thin photographing lens for mobile devices with cameras, which has a short total length and an exit angle up to around 20&#xb0; and corrects various aberrations.

The present invention provides a compact, thin zoom lens. The zoom lens according to the present invention includes, from an object side to an image plane side, a first lens group having an overall negative overall refractive power, a second lens group having an overall positive refractive power; and a third lens group having an overall positive refractive power. The first lens group includes a first lens and a second lens bonded together and having a negative refractive power. The second lens group includes a third lens with a positive refractive power, and a fourth lens and a fifth lens bonded together and having a negative refractive power. The third lens group includes a sixth lens having a positive refractive power. As a result, the total length is reduced, the retracted length can be reduced, and the zoom lens can be compact and thin.

A zoom lens with a slim and compact design has arranged in sequence from the object side to the image plane side a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. The first lens group is formed from a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens group is formed from a third lens having a positive refractive power and a fourth lens and a fifth lens. The fourth and fifth lens are joined together and have a negative refractive power. The third lens group is formed from a sixth lens having a positive refractive power. The zoom lens has a short length when retracted and extended, and a design that is compact and thin.

The present invention provides a high-performance, thin wide-angle lens suitable for imaging elements with high pixel counts. The wide-angle lens includes, from an object side to an image plane side: a first lens group including a first lens having a negative refractive power and a second lens having a positive refractive power; and a second lens group including a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a positive refractive power. The fourth lens is bonded to the third lens. The fifth lens is formed with at least one of its convex surfaces being an aspherical surface.

Wide-angle lens

The present invention provides a high-performance, thin wide-angle lens suitable for imaging elements with high pixel counts. The wide-angle lens includes, from an object side to an image plane side: a first lens group including a first lens having a negative refractivity and a second lens having a positive refractivity; and a second lens group including a third lens having a negative refractivity, a fourth lens having a positive refractivity, and a fifth lens having a positive refractivity. The fourth lens is bonded to the third lens. The fifth lens is formed with at least one of its convex surfaces being an aspherical surface.

Growing community of inventors

Toda, Japan

Yasuhiko Abe