Abstract: A light concentrator assembly includes a Fresnel lens, a plano-concave lens, and a CPC. The CPC is aligned with the Fresnel lens and the plano-concave lens. The Fresnel lens unit is configured for converging parallel light transmitted the Fresnel lens. The plano-concave lens is configured for further concentrating the light from the Fresnel lens before the light converged at a point. The CPC is configured for reflecting and directing the light beams from the plano-concave lens to exit through a light output opening of the CPC. The light concentrator assembly has a large incident acceptance angle.

Abstract: A light concentration element assembly includes a Fresnel lens unit and a compound parabolic concentrator. The Fresnel lens unit includes a first Fresnel lens and a second Fresnel lens arranged parallel with each other, and configured for converging light transmitted therethrough. The compound parabolic concentrator includes at least two paraboloidal reflecting surfaces. The parabolic concentrator includes a light incident opening facing the Fresnel lens unit and a light output opening, and the paraboloidal reflecting surfaces are configured for reflecting the converged light from the Fresnel lens unit and outputting the reflected light through the light output opening. A solar cell apparatus using the light concentration element assembly is provided.

Abstract: An all-reflective optical system includes a primary mirror of ellipsoidal configuration, a secondary mirror of hyperboloidal configuration facing the primary mirror, and an eye-piece that includes: a positive-powered tertiary mirror having a majority of positive power that is expected in the eye-piece and configured to substantially collimate light rays incident thereon; and a negative-powered near-flat quaternary mirror having lesser power than the tertiary mirror and configured to receive the substantially collimated light rays from the tertiary mirror, further collimate the received light rays and reflect the further collimated light rays to an exit pupil. The primary mirror, the secondary mirror and the eye-piece thereby form an afocal optical system.

Abstract: A projection optical system satisfies a conditional formula: 0.01<{(tan ?f1?tan ?f2)?(tan ?n1?tan ?n2)}·(?2/?1)<0.

Abstract: A fixed-focus lens disposed between a magnified side and a minified side. The fixed-focus lens has an optical axis and includes a reflective system and a refractive system. The reflective system includes a reflection mirror with a negative refractive power. The refractive system is disposed between the reflection mirror and the minified side and includes a first lens group and a second lens group. The first lens group has a positive refractive power. The second lens group is disposed between the first lens group and the minified side, and has a positive refractive power. The fixed-focus lens satisfies F/H>0.23, where F is an effective focal length and H is an image height.

Abstract: An annular inclined surface is formed on an edge portion of a first plastic lens in such a manner that the inclined surface surrounds a concave surface formed in a second surface of the first plastic lens. The inclined surface reflects unwanted light reflected by the concave surface so as to prevent the unwanted light from passing through the non-shading portion of the edge portion outside the effective area of a lens portion and then being reflected on an imaging area. This can suppress ghosting and flare due to the reflection of the unwanted light on the imaging surface.

Abstract: A lens adapted to image a first image plane at a reduced side onto a magnified side is provided. The lens has an optical axis. The lens includes a lens group and a concave reflective mirror. The lens group is disposed in the light path between the reduced side and the magnified side. The concave reflective mirror is disposed in the light path between the lens group and the magnified side. The offset of the first image plane with respect to the optical axis is greater than 100%. The throw ratio of the lens is less than 0.3.

Abstract: One embodiment of a method of calculating an optical surface comprises calculating a meridional optical line of the surface. A ray is selected that passes a known point defining an end of a part of the optical line already calculated. The optical line is extrapolated from the known point to meet the ray using a polynomial with at least one degree of freedom. The polynomial is adjusted as necessary so that the selected ray is deflected at the extrapolated optical line to a desired target point. The polynomial is added to the optical line up to the point where the selected ray is deflected. The point where the selected ray is deflected is used as the known point in a repetition of those steps.

Abstract: According to one embodiment relates to an optical system radially downsized and corrected well for aberration and is applicable, for example, to an aberration measuring apparatus for measuring wavefront aberration of a liquid immersion projection optical system. A catadioptric system of a coaxial type is provided with a first optical system which forms a point optically conjugate with an intersecting point with the optical axis on a first plane intersecting with the optical axis, on a second plane, and a second optical system which guides light from the first optical system to a third plane. The first optical system has a first reflecting surface arranged at or near the first plane, a second reflecting surface having a form of an ellipsoid of revolution the two focuses of which are aligned along the optical axis in a state in which one focus is located at or near a first light transmissive portion, and a medium filling an optical path between the first reflecting surface and the second reflecting surface.

Abstract: Provided is an imaging lens, the imaging lens including in an orderly way from an object side, a first lens including an incidence surface having a positive (+) refractive power and incident with light, a reflecting surface reflecting the incident light and an exit surface outputting the reflected light; a second lens having a negative (?) refractive power; a third lens having a positive (+) refractive power; a fourth lens having a positive (+) refractive power; a fifth lens having a negative (?) refractive power; a sixth lens having a positive (+) refractive power; and a seventh lens having a positive (+) refractive power, wherein the second lens through the seventh lens are disposed in an orderly way from an exit surface of the first lens.

Abstract: A laterally emitting radiation-generating component comprising a radiation source, the optical axis of which runs perpendicular to a mounting area of the component, and comprising an optical device arranged downstream of the radiation source. The optical device includes a reflective surface shaped like a V in cross section and a refractive surface that is shaped convexly as seen externally and is arranged between the reflective surface and a bottom area facing the radiation source. The bottom area is arranged and formed in such a way that through it electromagnetic radiation from the radiation source couples into the optical device. The reflective surface is arranged and formed in such a way that a central first portion of the coupled-in radiation is deflected toward the refractive surface by the reflective surface.

Abstract: Reflectors having concave reflecting surfaces (e.g., parabolic reflectors) and electronically controlled beam steering elements are used for rapid, low-diversion, wide-angle, and precision steering of optical beams, including laser beams.

Abstract: An inspection system including a catadioptric objective that facilitates dark-field inspection is provided. The objective includes an outer element furthest from the specimen having an outer element partial reflective surface oriented toward the specimen, an inner element nearest the specimen having a center lens comprising an inner element partial reflective surface oriented away from the specimen, and a central element positioned between the outer lens and the inner lens. At least one of the outer element, inner element, and central element has an aspheric surface. The inner element is spatially configured to facilitate dark-field inspection of the specimen.

Abstract: An optical device is disclosed including: a non-imaging secondary concentrator having an entry aperture and an exit aperture, and configured to receive light focused by a primary focusing element from a source onto the entry aperture. The non-imaging secondary concentrator includes: a first portion proximal the entry aperture which is rotationally symmetric about an optic axis; and a second portion proximal the exit aperture which is not rotationally symmetric about the optic axis.

Abstract: Reflectors having concave reflecting surfaces (e.g., parabolic reflectors) and electronically controlled beam steering elements are used for rapid, low-diversion, wide-angle and precision steering of optical beams, including laser beams.

Abstract: An Abbe prism lens and lens array are disclosed. The lens comprises front lenses disposed on a front surface of the Abbe prism, rear lenses disposed on a rear surface of the Abbe prism, a front bottom reflecting surface, a rear bottom reflecting surface, a left top reflecting surface, and a right top reflecting surface. An aperture cover is positioned over the front surface of the Abbe prism lens and a field cover is positioned over the rear surface of the Abbe prism lens. The aperture cover comprises aperture holes encircling the aspherical front lenses. The field cover comprises field holes encircling the aspherical rear lenses. Light enters the Abbe prism lens and reflects off the front bottom reflecting surface, reflects off the left top reflecting surface and the right top reflecting surface, reflects off the rear bottom reflecting surface, and exits the rear lens of the Abbe prism lens.

Abstract: A wide-angle projection optical system includes a first lens set with positive power, an aperture stop, a second lens set with positive power, a third lens set with negative power, and a negative power reflecting mirror. The first lens set provides optical characteristics to match with a light beam coming from the object side. The second lens set is arranged behind the aperture stop to converge the light beam. The third lens set is configured to diverge the light to enlarge a full field angle. The negative power reflecting mirror is configured to further enlarge the full field angle and correct image distortion. The first lens set, the second lens set, the third lens set and the reflecting mirror have a common optical axis. The optical axis is shifted with respect to a center of a micro display.

Abstract: A projection optical system for enlarging and projecting a light flux from an image display panel modulating an irradiation light, onto a screen in an oblique direction, the projection optical system includes: a lens system including a plurality of lenses, the lens system refracting the light flux from the image display panel; a single convex mirror reflecting the light flux from the lens system, the lens system and the convex mirror being arranged in an order from the image display panel; and a stop disposed in an optical path after an emission from the lens system to an incidence on the convex mirror.

Abstract: A fixed-focus lens adapted to be disposed between a primary image side and a second image side is provided. The fixed-focus lens includes a second lens group, a first lens group, and a curved reflector arranged in sequence from the primary image side to the second image side. The second lens group includes a first lens, a second lens, and a third lens arranged in sequence from the primary image side to the second image side. The first lens and the third lens have positive refractive powers and each of the first lens, the second lens, and the third lens is a spherical lens.

Abstract: A lens adapted to image a first image plane at a reduced side onto a magnified side is provided. The lens has an optical axis. The lens includes a lens group and a concave reflective mirror. The lens group is disposed in the light path between the reduced side and the magnified side. The concave reflective mirror is disposed in the light path between the lens group and the magnified side. The offset of the first image plane with respect to the optical axis is greater than 100%. The throw ratio of the lens is less than 0.3.

Abstract: A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein an interval between at least any two lens units is changed so that an optical image is formed with a continuously variable magnification, the zoom lens system comprises a first lens unit having positive power, a second lens unit that includes a lens element having a reflecting surface and has negative power and subsequent lens units including at least one lens unit having positive power, and the condition: 0.50<(C?S)/H<1.00(C=?(2R·dR?dR2), S is a sag of the image side surface of the most object side lens element in the second lens unit at height H, H is one-half of an optical axial thickness of the lens element having a reflecting surface, R is a radius of curvature of the image side surface, and dR is an interval between the most object side lens element and the lens element having a reflecting surface) is satisfied.

Abstract: A light-collecting device has a hollow at center. Three layers are sequentially pasted on and around the hollow. The device collects light efficiently with different materials of the layers. And the device has a long life of use, is environmentally friendly and is easily mass-produced.

Abstract: A variety of lenses, lens assemblies, imaging devices, applications for such lenses, assemblies and devices, and related methods of operation and manufacturing are disclosed. At least some embodiments of the invention relate to a lens that includes first and second inward-facing surfaces that are each at least partly reflective. The lens further includes a first aperture that is positioned around at least a portion of an outer periphery of one of the first and second inward-facing surfaces, and a second aperture existing proximate a central region of the lens. The light proceeding within the lens between the first and second inward-facing surfaces is reflected at least twice on at least one of the first and second inward-facing surfaces as it travels between the first aperture and the second aperture.

Abstract: Illumination lenses (1806, 1902, 2002, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 3006, 3100) having surfaces shaped according to given differential equations in order to distribute light in a highly controlled manner with minimum reflection losses are provided. Both primary lenses and secondary lenses are provided. The secondary lenses include outer surfaces that are defined as loci of constant optical distance from an origin at which a light source is located. Versions are provided of both the primary and secondary lenses having Total Internal Reflection (TIR) wings. These are useful in the case that narrower distributions of light are required. A method of refining the shape of the lenses to obtain more obtain lenses that produce better fidelity ideal light distributions is also provided.

Abstract: A catadioptric objective configured to inspect a specimen is provided. The catadioptric objective includes a Mangin element having one surface at a first axial location and an extension element positioned together with the Mangin element. The extension element provides a second surface at a second axial location. Certain light energy reflected from the specimen passes to the second surface of the extension element, the Mangin element, and through a plurality of lenses. An aspheric surface may be provided, and light energy may be provided to the specimen using diverting elements such as prisms or reflective surfaces.

Abstract: A wide-angle projection lens module is provided, including a reflective convex aspheric mirror and a refractive lens group of positive refractive power. The following Conditions (1) to (2) are satisfied: 15<|Freflective/F|<25 ??Condition (1), and 1.5<|Frefractive/f|<2.0 ??(Condition (2), wherein, F is a focal length of the wide-angle projection lens module, Freflective is a focal length of the reflective convex mirror, and Frefractive is a focal length of the refractive lens group.

Abstract: An optical element that is made of a transparent medium L1 rotationally symmetric relative to the central axis 2 with a refractive index greater than 1, wherein the transparent medium L1 has a first transmissive surface 11, a first reflective surface 12, a second reflective surface 13 arranged at an opposite side to the image plane 5 relative to the first reflective surface 12 and a second transmissive surface 14 arranged at the image plane 5 side relative to the second reflective surface 13 and that the flux of light entering the transparent medium L1 goes into it by way of the first transmissive surface 11 so as to be reflected to the opposite side to the image plane 5 by the first reflective surface 12 and then to the image plane 5 side by the second reflective surface 13 to form an optical path before going out from the transparent medium L1 at the image plane 5 side by way of the second transmissive surface 14 in the order of forward ray tracing.

Abstract: A high efficiency and compact optical device comprising two or more active and resonating optical facet surfaces defined by a three-dimensional representation and configured to provide a three-dimensional device. A focal region, remote from the optical surfaces and non-contiguous therewith, is defined by two or more active optical resonant surfaces, at least one of which is self-resonant. The optical surfaces in general do not have a continuous second derivative and are defined by a piecewise continuous surface function providing radially directed facets. The optical device comprises a transparent dielectric body with its optical surfaces being formed on the surfaces of said transparent dielectric body. A light transducer may be located at a focal region to provide an energy conversion. A light source having a physical extension in space, such as an LED, may be located at the focal region to provide collimation.

Abstract: A wide-angle projection lens module is provided, including a reflective convex aspheric mirror and a refractive lens group of positive refractive power. The following Conditions (1) to (2) are satisfied: 15<|Freflective/F|<25??Condition (1); and 1.5<|Frefractive/F|<2.0??Condition (2), wherein, F is a focal length of the wide-angle projection lens module, Freflective is a focal length of the reflective convex mirror, and Frefractive is a focal length of the refractive lens group.

Abstract: A catadioptric system is provided comprising a correcting plate and an optical system. The correcting plate is configured to condition electromagnetic radiation to correct at least one aberration. The optical system is configured to reflect a first portion of the conditioned electromagnetic radiation, to refract a second portion of the conditioned electromagnetic radiation, and to focus the reflected first portion of the conditioned electromagnetic radiation onto a target portion of a substrate. The first portion of the electromagnetic radiation is not refracted by an optical element, allowing the catadioptric optical system to operate in a broad spectral range.

Abstract: An image system adapted to a projection display apparatus includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, an aspheric reflector, and a curved reflector. The second lens group includes an aspheric lens which is the nearest to the light valve in the second lens group. A material of the aspheric lens includes glass, the thermal-optical coefficient of the glass is between 1.0×10?6/K and 12.5×10?6/K, and the refractive index of the glass is between 1.482 and 1.847. The aspheric reflector is disposed front of the first lens group for reflecting the image beam passing through the first lens group and second lens group. The curved reflector is disposed above the first lens group for reflecting the image beam reflected by the aspheric reflector onto the screen. The image system has a good imaging quality.

Abstract: A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein an interval between at least any two lens units is changed so that an optical image is formed with a continuously variable magnification, the zoom lens system comprises a first lens unit having positive power, a second lens unit that includes a lens element having a reflecting surface and has negative power and subsequent lens units including at least one lens unit having positive power, and the condition: 0.50<(C?S)/H<1.00(C=?{square root over ( )}(2R·dR?dR2), S is a sag of the image side surface of the most object side lens element in the second lens unit at height H, H is one-half of an optical axial thickness of the lens element having a reflecting surface, R is a radius of curvature of the image side surface, and dR is an interval between the most object side lens element and the lens element having a reflecting surface) is satisfied.

Abstract: A lighting device can have a simple configuration which can be formed compactly in the direction of its optical axis in particular, and with a light weight. The lighting device can also have a functional, three-dimensional innovative appearance for the sake of enhanced merchantability and novelty. The lighting device can include a light source and a projection lens which is situated so that its source-side focus lies near the light source and its optical axis generally coincides with that of the light source. The projection lens can be a distribution control lens of convex form, having an exit surface shaped aspherically so that the direction of emission is continuously refracted into specified directions with respect to the angle of incidence from the focal position.

Abstract: Reflectors having concave reflecting surfaces (e.g., parabolic reflectors) and electronically controlled beam steering elements are used for rapid, low-diversion, wide-angle, and precision steering of optical beams, including laser beams.

Abstract: A projection image display device is disclosed in which a trapezoidal distortion and/or aberration are restrained when an image is enlarged and projected obliquely onto a screen. An image generator is connected to an optical system base in such a manner that at least an inclination thereof (on an axis parallel to X axis) with respect to a vertical line and a distance thereof in forward and backward direction (Z axis direction) can be adjusted by an adjusting mechanism. Further, a projecting lens 2 as a first optical system and a free-form curved surface mirror as a second optical system are fixed to the optical system base. The free-form curved surface mirror is rotatable (on an rotary axis parallel to X axis) with respect to the vertical line at a substantial center of the free-form curved surface mirror.

Abstract: A radar apparatus has a light receiver that includes a refractive body and a mirror on an opposite surface of the refractive body relative to an incidence surface of the refractive body for receiving an incident light from an outside of the radar apparatus. The refractive angle of the refractive body is configured to be smaller than an incident angle of the incident light, and the mirror is configured to reflect at least a portion of the incident light toward a first light receiving element that is disposed on the incidence surface with its light receiving face facing the incidence surface of the refractive body.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a single prism. When image-side three surfaces of the prism are defined as a surface A, a surface B and a surface C in order from the image plane side thereof, at least one of the surfaces B and C has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The optical system leads light rays from an object to the image plane without forming an image in the prism and has a pupil in the prism. The surface A is a transmitting surface through which rays exit from the prism. The surfaces B and C are internally reflecting surfaces, which are positioned to face each other to form a Z-shaped optical path.

Abstract: An image pickup optical system includes, in order from the object side, a front unit having at least one reflecting surface with power that is rotationally asymmetrical, an aperture stop, and a rear unit having at least one reflecting surface with power that is rotationally asymmetrical. In this case, F-numbers in two directions perpendicular to each other on a plane perpendicular to the optical axis are different. Decentration takes place in one of the two directions and the F-number in a direction perpendicular to a decentering direction is smaller than that in the decentering direction. When the F-number in the decentering direction is represented by FNY and the F-number in the direction perpendicular to the decentering direction is represented by FNX, the optical system satisfies the following condition: 1.1<FNY/FNX<2.0.

Abstract: A catadioptric projection objective with telecentric image space has a first objective part configured to image the pattern from the object surface into a first intermediate image, and having a first pupil surface, a second objective part configured to image the first intermediate image into a second intermediate image, and having a second pupil surface optically conjugate to the first pupil surface, the second objective part including a concave mirror having a reflective mirror surface positioned at or close to the second pupil surface, and a third objective part configured to image the second intermediate image into the image surface, and having a third pupil surface optically conjugate to the first and second pupil surface.

Abstract: A catadioptric imaging optical system of a high numerical aperture in which various aberrations are properly corrected without using a reflection surface having an aspherical shape of high order or a reciprocal optical element. The catadioptric imaging optical system forms an image of a first plane on a second plane and includes a first imaging system for forming a first intermediate image of the first plane based on light from the first plane, a second imaging system having two concave reflection mirrors for forming a second intermediate image of the first plane based on light from the first intermediate image, and a third imaging system for forming a final image of the first plane on the second plane based on light from the second intermediate image. The two concave reflection mirrors have prolate spheroidal-shaped reflection surfaces.

Abstract: A projection display system and method is provided. One or more light sources, such as solid state lasers, generates light of various colors that is modulated by a spatial light modulator, such as a digital micro-mirror device. The projection optics of the system include a telecentric rear group of lenses followed by a pair of aspheric lenses formed of a continuous piece of material. A folding mirror, such as a single-piece or multi-piece angular mirror, is disposed along the optical path between the aspheric lenses, to reduce the depth of the enclosure, and an aspheric mirror projects the image onto a projection screen. A folding mirror may be used after the aspheric mirror to further reduce the depth of the enclosure.

Abstract: A method for optimizing cost and performance in a lens assembly is disclosed. The method relaxes the constraints of optically correcting lateral chromatic aberration and distortion on the lens assembly and instead electronically corrects for lateral chromatic aberration and distortion. As a result the lens assembly transmissivity and MTF improve dramatically and other aberrations are reduced as a result of re-optimizing the lens assembly merit function. The cost and volume of the lens assembly are reduced as well. The optimized lens assembly could be used in rear or front projection display devices as a well as image acquisition devices.

Abstract: An LED illumination module has a light-emitting diode and a rotationally symmetrical, one-piece, light-transparent adapter lens centered on a lens axis. This lens has an axially rearwardly open blind hole defined by a radially inwardly directed frustoconical light-receiving side surface and an axially rearwardly directed convex light-receiving base surface. The diode is axially shiftable in the hole. An axially forwardly directed convex light-output surface is coaxially surrounded by an axially forwardly directed and forwardly flaring frustoconical light-output surface. A radially outwardly directed and radially inwardly reflective surface extends generally from a front edge of the axially forwardly directed frustoconical light-output surface to a rear edge of the radially inwardly directed frustoconical surface.

Abstract: An illumination optical system, an illumination unit, and an image projection apparatus employing the same are provided. The illumination optical system includes a light source irradiating a diverging light, a reflection optical system condensing the diverging light from the light source, and a lens optical system projecting the light condensed by the reflection optical system. The reflection optical system is comprised of an aspherical concave mirror. The lens optical system comprises a condensing lens having a positive refractive power in a central part and a refractive power of the condensing lens being decreased toward a circumferential part. Optical efficiency may be improved even when a light-emitting surface of the light source is relatively large and the light source cannot be regarded as a point light source.

Abstract: A projection-type display device 1 including a light source 10, an optical integrator 20, dichroic mirrors 30 and 35, a reflecting mirror 36, a relay optical system 40, parallelizing lenses 50B, 50G and 50R, liquid crystal light valves 60B, 60G and 60R, incident side lenses 70B, 70G and 70R, a light-synthesizing cross dichroic prism 80, a relay lens 90, an emergent side lens 95, a liquid crystal light valve 100 and a projection lens 110, and liquid crystal light valve 100 is provided in the rear stage of liquid crystal light valves 60B, 60G and 60R.

Abstract: The present invention provides an optical system for illuminating and viewing a target in which an illumination element and a receiving means are disposed behind a single optical window, and which obtains data essentially free of backscatter and stray light. The optical window of the optical system is configured such that it defines a shape having at least one focal curve, i.e., an ellipsoid shaped dome. The illumination element and the receiving means are geometrically positioned on the focal curve plane or in proximity of the focal curve plane, such that, when illuminating, rays from the illumination elements, that are internally reflected from the optical window, will not be incident on the receiving means.

Abstract: Disclosed are an imaging device and a display device which both have a simple structure without any need of an image conversion. The imaging device includes a lens component group including multiple lens component systems, each of which focuses incident light from the object, thereby creating a non-inverted image of the object, the lens component systems being arranged in an array form and on the same level, and an image capturing mechanism for picking up the created image. In addition, each of the lens component systems includes an afocal optical system and an image-forming system. The afocal optical system includes at least one optical element for inverting an externally incident light ray relative to its optical axis and outputting the light ray. The optical element has uniform refractive index. The image-forming system includes at least one optical element having uniform refractive index throughout its interior.

Abstract: In a head up display apparatus adapted to be mounted on a head in the goggle type or the head gear type and enable a video image to be observed, wherein an original image is directed to an eyeball through a reflecting optical system to enable the image to be observed, one or more members differing in power depending on the azimuth direction are present in the reflecting optical system, and the members are designed to have an aspherical surface action in the cross-section of at least one azimuth direction.

Abstract: An objective comprising axial symmetry, at least one curved mirror and at least one lens and two intermediate images. The objective includes two refractive partial objectives and one catadioptric partial objective. The objective includes a first partial objective, a first intermediate a image, a second partial objective, a second intermediate image, and a third partial objective. At least one of the partial objectives is purely refractive. One of the partial objectives is purely refractive and one is purely catoptric.

Abstract: An aspheric reduction objective has a catadioptric partial objective (L1), an intermediate image (IMI) and a refractive partial objective (L2). The catadioptric partial objective has an assembly centered to the optical axis and this assembly includes two mutually facing concave mirrors (M1, M2). The cutouts in the mirrors (B1, B2) lead to an aperture obscuration which can be held to be very small by utilizing lenses close to the mirrors and having a high negative refractive power and aspheric lens surfaces (27, 33). The position of the entry and exit pupils can be corrected with aspherical lens surfaces (12, 48, 53) in the field lens groups. The number of spherical lenses in the refractive partial objective can be reduced with aspherical lens surfaces (66, 78) arranged symmetrically to the diaphragm plane. Neighboring aspheric lens surfaces (172, 173) form additional correction possibilities.