161results about How to "Reduce spherical aberration" patented technology

Multifocal and single focus lenses are defined by nonconical aspheric optical surfaces. Various alternative surface shapes provide one or more vision regions bounded by optical steps. Each optical step has rapidly and smoothly changing power in the radial direction which creates an induced aperture through which the cortical elements of the human vision system are induced to concentrate. The induced aperture results in increased clarity and enhanced vision. In various configurations, the induced aperture decreases spherical aberration to further enhance vision. To increase correction intensity at one or more powers, redundant power regions are provided in repeated optical steps or annular apertures. In several embodiments, the redundant power regions create multiple induced apertures at one or more optical powers directed at one or more vision distances.

An imaging lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with negative refractive power has a convex object-side surface and a concave image-side surface. The second lens element has positive refractive power. The third lens element has refractive power. The fourth lens element with refractive power has an object-side surface and an image-side surface being aspheric. The fifth lens element with positive refractive power has an object-side surface and an image-side surface being aspheric. The sixth lens element with negative refractive power has a concave image-side surface, wherein at least one reflection point is formed on the image-side surface thereof.

The projection zoom lens system includes a negative first lens group, a positive second lens group, a third lens group, a positive fourth lens group, a fifth lens group, and a positive sixth lens group. The lens system is nearly telecentric on a reduction side. During zooming, the second to fifth lens groups are moved while the first and six lens groups remain stationary. The third lens group includes a positive lens LP having a convex surface directed to a magnification side, and a negative lens LN having a concave surface which is directed to the reduction side and has a curvature stronger than a magnification-side surface of the negative lens LN. The conditional expression of 5.0≦|fG3 / RLN-2| is satisfied. Here, fG3 denotes a focal length of the third lens group, and RLN-2 denotes a radius of curvature of the reduction-side surface of the negative lens LN.

To provide a compact image forming optical system in which an incident angle to an imaging plane of a solid-state imaging device is small and whose chromatic aberration, astigmatism, field curvature, and distortion are reduced. An image forming optical system of a first embodiment of the present invention comprises four lenses arranged from the object side to the imaging plane side in order, that are a first lens that is a double-convex lens, a second lens that is a double-concave lens, a third lens that is a positive meniscus lens that is convex toward an image side, and a fourth lens that is a negative meniscus lens that is convex toward an object side. An aperture is placed closer to the object than the image side surface of the first lens. The image forming optical system of the first embodiment of the present invention satisfies the following equations, where fi is an absolute value of a focal length of i-th lens, f is an absolute value of a focal length of a whole optical system, vdi is Abbe's number of i-th lens, and TTL is a distance from the object side surface of the first lens, in the object side surface and an aperture side surface, to the imaging plane.0.425<f1 / f4<0.7  (1)25<vd2<28  (2)50<vd1,vd3,vd4<57  (3)0.595<f2 / f4<1.05  (4)1.5<f / f1<2.2  (5)f1<f3  (6)1.05<TTL / f<1.18  (7)

A focusing apparatus for use with an optical system having a high NA objective lens includes an image forming and capturing apparatus for forming an image in an intermediate image zone, and for capturing an image by receiving and refocusing light from a selected focal plane within the intermediate image zone, and a focus adjusting apparatus for adjusting the position of the selected focal plane within the intermediate image zone. The image forming and capturing apparatus includes at least one high NA lens. In use, spherical aberration introduced by the high NA objective lens is reduced.