Abstract: A vision assisting apparatus includes a casing for forming an inversely U-shaped optical path, a light entry, provided at one end of the optical path, through which light enters, a light exit, provided at another end of the optical path, through which light exits in an opposite direction to the light entry, an optical system for processing an image entered via the light entry by using the optical pass and outputting a processed image via the light exit, and attaching structure for attaching the casing to a wearer so that the light exit is positioned close to an eye of the wearer. By forming the inversely U-shaped optical path with the casing, it is possible to provide a sufficiently long optical path in a compact form.

Abstract: A zoom lens includes first to fourth lenses in order from an object side. The first lens has negative refracting power and a concave surface thereof faces the object side. The second and fourth lenses have positive refracting power. The third lens has negative refracting power. The zoom lens as a whole is constituted of a first lens group having positive refracting power, and a second lens group having negative refracting power. The following conditions are satisfied, ?2.7<fs/f1<?1.7 ?1.1<f1/f2<?0.9 and 1.0<r1/f1<3.0, wherein fs denotes a focal length of the overall system at a wide-angle end, f1 and f2 denote focal lengths of the first and second lenses respectively, and r1 denotes a radius of curvature at the object side of the first lens.

Abstract: The vision assisting apparatus of the present invention includes a casing for forming an inversely U-shaped optical path, a light entry, provided at one end of the optical path, through which light enters, a light exit, provided at another end of the optical path, through which light exits in an opposite direction to the light entry, an optical system for processing an image entered via the light entry by using the optical pass and outputting a processed image via the light exit, and means for attaching the casing to a wearer so that the light exit is positioned close to an eye of the wearer. By forming the inversely U-shaped optical path with the casing, it is possible to provide a sufficiently long optical path in a compact form.

Abstract: A zoom lens includes first to fourth lenses in order from an object side. The first lens has negative refracting power and a concave surface thereof faces the object side. The second and fourth lenses have positive refracting power. The third lens has negative refracting power. The zoom lens as a whole is constituted of a first lens group having positive refracting power, and a second lens group having negative refracting power. The following conditions are satisfied, −2.7<fs/f1<−1.7 −1.1<f1/f2<−0.9 and 1.0<r1/f1<3.0, wherein fs denotes a focal length of the overall system at a wide-angle end, f1 and f2 denote focal lengths of the first and second lenses respectively, and r1 denotes a radius of curvature at the object side of the first lens.

Abstract: A zoom lens comprises a plurality of lens elements arranged into three zooming lens units. These zooming lens units are spaced from one another by axial distances that vary during zooming. The lens units are a negative power front lens unit, a positive power middle lens unit and a negative power rear lens unit. At least one of the lens units continually moves away from the image plane, as the zoom lens zooms from a wide angle position toward a telephoto position so that the distance from this lens unit to the image plane varies in sigmoidal relation with respect to the focal length of the zoom lens.