72results about How to "Low F-number" patented technology

A comparatively low f-number, compact two-group zoom lens that corrects aberrations in the visible and the near-infrared regions includes, in order from the object side, a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes three lens components that are lens elements of negative, negative, negative, and positive refractive power, respectively, in order from the object side. The second lens group includes four lens components that are lens elements of positive, positive, negative, and positive refractive power, respectively, in order from the object side. Aspheric surfaces are disclosed. Certain conditions relating to the focal lengths of the two lens groups, the indexes of refraction, and Abbe numbers of various lens elements are satisfied to control aberrations in both the visible and the near-infrared regions.

A tunable Fabry-Perot filter that is less sensitive to angle of incidence is formed by replacing the cavity (air gap) with a partitioned cavity that has an effective refractive index greater than one. The partitioned cavity includes a pair of partitioned cavity dielectric layers formed on the reflectors on either side of the variable air gap. Each of the dielectric layers has an optical thickness that is less than one fourth the shortest wavelength in the tuning range of the filter. The resulting three-layer partitioned cavity has an effective optical thickness substantially equal to an integral multiple (m) of one half the transmitted wavelength within the tuning range of the filter.

A folded camera that includes two light folding elements such as prisms and an independent lens system, located between the two prisms, which includes an aperture stop and a lens stack. The lens system may be moved on one or more axes independently of the prisms to provide autofocus and / or optical image stabilization for the camera. The shapes, materials, and arrangements of the refractive lens elements in the lens stack may be selected to capture high resolution, high quality images while providing a sufficiently long back focal length to accommodate the second prism.

There is provided an imaging lens with small telephoto ratio and excellent optical characteristics which satisfies demand of the downsizing, the low-profileness and the low F-number. An imaging lens comprises, in order from an object side to an image side, a first lens with positive refractive power, a second lens, a third lens, a fourth lens being a double-sided aspheric lens, a fifth lens being a double-sided aspheric lens, and a sixth lens having a convex surface facing the image side, and a below conditional expression is satisfied:0.60<TTL / f<1.00whereTTL: a total track length, andf: a focal length of the overall optical system of the imaging lens.

There is provided an imaging lens with excellent optical characteristics which satisfies demand of wide field of view, low profile and low F-number. An imaging lens comprises, in order from an object side to an image side, a first lens, an aperture stop, a second lens with positive refractive power in a paraxial region, a third lens with negative refractive power in the paraxial region, a fourth lens, a fifth lens with the positive refractive power in the paraxial region, a sixth lens being a double-sided aspheric lens, and a seventh lens with negative refractive power having an image-side surface being concave in the paraxial region and an aspheric surface having at least one pole point in a position off the optical axis.

There is provided an imaging lens with excellent optical characteristics which satisfies demand of low-profileness and low F-number. An imaging lens comprises, in order from an object side to an image side, a first lens with positive refractive power having an object-side surface being convex in a paraxial region, a second lens with negative refractive power in a paraxial region, a third lens with negative refractive power in a paraxial region, a fourth lens with positive or negative refractive power having an object-side surface being convex in a paraxial region, a fifth lens with positive or negative refractive power in a paraxial region, and a sixth lens with positive or negative refractive power having an image-side surface being convex in a paraxial region, and predetermined conditional expressions are satisfied.

There is provided a compact imaging lens which meets demand of low-profileness, reduction in telephoto ratio and low F-number, and properly corrects aberrations. An imaging lens comprising in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens having a convex surface facing the image side near an optical axis, and a fifth lens having positive refractive power, wherein a below conditional expression (1) is satisfied:0.64<TTL / f<1.0  (1)wheref: focal length of the overall optical system of the imaging lens, andTTL: distance along the optical axis from an object-side surface of the first lens to an image plane.

There is provided an imaging lens with excellent optical characteristics which satisfies demand of wide field of view, low-profileness and low F-number in well balance.An imaging lens comprises in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens having a concave surface facing the object side near an optical axis, a fifth lens, and a sixth lens having the concave surface facing the image side near the optical axis and negative refractive power, wherein said second lens has a convex surface facing the object side near the optical axis, composite refractive power of said second lens, said third lens and said fourth lens is negative, and below conditional expressions (1) and (2) are satisfied:0.85<vd1 / (vd2+vd3)<1.95  (1)0.15<vd5 / vd6<0.55  (2)wherevd1: abbe number at d-ray of the first lens,vd2: abbe number at d-ray of the second lens,vd3: abbe number at d-ray of the third lens,vd5: abbe number at d-ray of the fifth lens, andvd6: abbe number at d-ray of the sixth lens.

There is provided an imaging lens with excellent optical characteristics which satisfies demand of a low profile and a low F-number. An imaging lens comprises in order from an object side to an image side, a first lens with negative refractive power having an object-side surface being convex in a paraxial region, a second lens with positive refractive power in a paraxial region, a third lens with the negative refractive power in a paraxial region, a fourth lens with the positive refractive power in a paraxial region, a fifth lens having a flat object-side surface and a flat image-side surface that are aspheric, and a sixth lens with the negative refractive power having an image-side surface being concave in a paraxial region.

There is provided an imaging lens which satisfies demand of the wide field of view, the low-profileness and the low F-number and has excellent optical performance. An imaging lens comprises, in order from an object side to an image side, a first lens having positive refractive power and a convex surface facing the object side near an optical axis, a second lens having the convex surface facing the object side near the optical axis, a third lens, a fourth lens, a fifth lens, and a sixth lens having negative refractive power and a concave surface facing an image side near the optical axis, wherein the second lens has negative refractive power near the optical axis, the third lens has the negative refractive power near the optical axis, the fourth lens has the positive refractive power near the optical axis, and below conditional expressions are satisfied:−3.00<(D2 / f2)×100<−0.050.25<(T4 / f)×100<1.00whereD2: thickness along the optical axis of the second lens,f2: focal length of the second lens,T4: distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens, andf: focal length of the overall optical system of the imaging lens.