159results about How to "Aberration suppression" patented technology

An imaging lens substantially includes six lenses, constituted by: a first lens having a negative refractive power, which is of a meniscus shape having a concave surface toward an image side; a second lens; a third lens; a fourth lens; a fifth lens having a positive refractive power; and a sixth lens having a negative refractive power, a concave surface toward the image side, and at least one inflection point in the surface toward the image side; provided in this order from an object side. The imaging lens satisfies a predetermined conditional formula.

A first lens group includes a plano-concave and negative first lens, a catoptric element having a flat object side surface and a flat image side surface, and a first cemented lens, for example. Here, the first cemented lens includes a negative second lens and a positive third lens in order from an object side. A second lens group includes an aperture stop and a positive second cemented lens, for example. The second cemented lens includes a positive fourth lens, a negative fifth lens, and a positive sixth lens in order from the object side. A zoom lens satisfies a conditional expression 1.59<n21<2.20, assuming that a value n21 indicates refractive index of the fourth lens on a side closest to an object in the second lens group.

A photographing optical 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 positive refractive power has an object-side surface being convex in a paraxial region. The second lens element has refractive power. The third lens element has positive refractive power. The fourth lens element has refractive power. The fifth lens element with positive refractive power has an object-side surface being convex in a paraxial region and an image-side surface being convex in a paraxial region. The sixth lens element with positive refractive power has an object-side surface being convex in a paraxial region and an image-side surface being concave in a paraxial region, and the image-side surface thereof has at least one inflection point.

An ophthalmic apparatus includes an aberration correction unit which corrects aberration occurring in light irradiating an eye to be examined; and a common optical system which is commonly provided for an optical path of irradiated light on the aberration correction unit and an optical path of reflected light from the aberration correction unit. The common optical system includes at least one optical element, and areas through which the irradiated light and the reflected light respectively pass overlap each other on the optical element.

An objective lens for an optical pick-up which is used to record data to and/or to reproduce data from at least three types of optical discs by selectively using one of at least three light beams having different wavelengths is provided. When thicknesses of a first, second and optical discs are represented by t1, t2 and t3, respectively, a relationship t1≦t2<t3 is satisfied. When numerical apertures required for the first, second and third optical discs are represented by NA1, NA2 and NA3, respectively, a relationship NA1≧NA2>NA3 is satisfied. The first, second and third light beams are incident on the objective lens as substantially collimated light beams, respectively. In this configuration, at least one of surfaces of the objective lens includes a first area for attaining the numerical aperture required for recording data to and/or reproducing data from the third optical disc, and a second area located outside the first area. The first area includes an inner area including an optical axis of the objective lens, and an outer area located outside the inner area. The outer area is configured to converge the third light beam on a data recording layer of the third optical disc with an amount of an aberration being substantially zero. The objective lens satisfies a condition: 0.75<h1a/h1<0.87 . . . (1), where h1 represents an effective radius of the first area, and h1a represents an effective radius of the inner area.

An infrared sensor includes: an infrared detecting device; a lens disposed above the infrared detecting device; an member that is disposed at a side of an upper surface of the lens and includes an opening; and a gap that intervenes between the member and the lens and has a wider range than the opening.

A zoom lens is provided and includes: in order from an object side thereof, a first lens group having a negative refractive power, a stop; a second lens group having a positive refractive power; and a third lens group having a positive refractive power. The magnification of the zoom lens is varied from a wide angle end to a telephoto end by changing a space between the first lens group and the second lens group and a space between the second lens group and the third lens group. The first lens group includes: in order from an object side thereof, a negative lens having at least one aspherical surface and having a concave surface on an image side thereof; and a positive meniscus lens having a convex surface on the object side thereof. The zoom lens satisfies conditional expressions specified in the specification.

There is provided an objective lens used for three types of optical discs including by selectively using one of three types of light beams. At least one of surfaces of the objective lens is provided with a first region converging the third light beam on a recoding surface of the third optical disc. The first region has a step structure configured to have concentric refractive surface zones and to give an optical path length difference to an incident beam at each step formed between adjacent refractive surface zones. The step structure is configured such that the optical path length difference given by each step is substantially equal to an odd multiple of a wavelength of a first light beam, and a value of differentiation of an optical path difference function defining the step structure crosses zero in a height ranging from 30% to 70% of an effective diameter of the first region.

An electron microscope is offered which facilitates aberration correction even during high-magnification imaging. The microscope has a spherical aberration corrector, a transfer lens system mounted between the corrector and an objective lens, an aperture stop mounted in a stage preceding the corrector so as to be movable relative to the optical axis, and an angular aperture stop mounted at or near the principal plane of the transfer lens system movably relative to the optical axis to adjust the angular aperture of the electron beam.