Abstract: An optical element for microscopic inspection of a surface. The optical element has an elongated body defining an optical axis, with a first end adjacent the surface and a second end directed toward an imaging instrument. The body has a curved reflective surface and an optical aperture at the first end, and defines first and second associated focal points on the optical axis. The first focal point is spaced apart from the first end of the body, such that positioning the surface at the first focal point generates an image of the surface at the second focal point. The reflective surface may be paraboloidal, with a concentrating lens focusing collimated rays to the second focal point, so that a conventional microscope may view the image generated at the second point.

Abstract: An aberration correction system having a first lens disposed at an object side; and a second lens disposed at an image side, wherein the first and second lenses have different dispersions (Abbe numbers) with respect to each other, the surface of the object side of the first lens and the surface of the image side of the second lens which is adjacent to the image have substantially common center of curvature and the first and second lenses rotate around the center of curvature.

Abstract: An optical image field splitting system which is adapted to allow a single camera to be used to view two or more images or object scenes of a single object or one or more images from a plurality of objects is disclosed. The optical image field splitting system includes a camera, a mirror pair, a lens, and a third mirror spaced apart from the mirror pair. The mirror pair includes a first mirror defining a first reflective planar surface and a second mirror defining a second reflective planar surface. The first reflective planar surface is oriented at a first predetermined angle relative to the second reflective planar surface. The lens is coupled to the camera and disposed in an optical path defined between the camera and the mirror pair. The third mirror defines a third reflective planar surface oriented at a second predetermined angle relative to the second reflective surface of the second mirror. An optical path length is defined between the third mirror and the second mirror.

Abstract: An apparatus for separating solar radiation into a longer wavelength component and a shorter wavelength component includes a concentrator of solar radiation, the concentrator having a focal point F.sub.1, and a mirror for selectively reflecting either the longer or the shorter wavelength component of the solar radiation spectrum. The mirror is positioned in the light path of solar radiation from the concentrator, the mirror having a focal point F.sub.2. The mirror includes a spectrally selective filter to make the mirror transparent to the non-reflected component of the solar radiation spectrum, thereby to allow the non-reflected component to pass through the mirror to a first receiver located at the focal point F.sub.1, and the mirror is appropriately curved in order to selectively concentrate and direct the reflected longer or shorter wavelength component to a second receiver located at the focal point F.sub.2.

Abstract: The present invention relates to a reflecting optical system, wherein the reflecting optical system comprises a first reflecting surface having a positive power and a second reflecting surface having a negative power, wherein at least one of the surfaces is inclined and the reflecting optical system comprises a substantially afocal optical system of the surfaces.

Abstract: In a catadioptric optical system, the first focusing lens system A includes a concave mirror Mc, and it forms an intermediate image of the first plane R. The second focusing lens system B includes an aperture stop AS, and it forms a refocused image of the intermediate image on the second plane W. A reflecting surface M.sub.P1 is placed so that the light flux leaving the first focusing lens system A is guided to the second focusing lens system B. There are one or more lens surfaces that satisfy the conditionh/.phi.<0.85 (1)and one or more lens surfaces that satisfy the condition0.85<h/.phi.<1.2 (2)where h is the height at each lens surface of the light beam that is assumed to be emitted from the intersection of the optical axis of the first plane and passes through the lens surfaces with the maximum numerical aperture, and .phi. is the radius of the diaphragm of the aperture stop.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter.

Abstract: An ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 .mu.m), comprises a focusing lens group with multiple lens elements that provide high levels of correction of both image aberrations and chromatic variation of aberrations over a selected wavelength band, a field lens group formed from lens elements with at least two different refractive materials, such as silica and a fluoride glass, and a catadioptric group including a concave reflective surface providing most of the focusing power of the system and a thick lens providing primary color correction in combination with the focusing lens group. The field lens group is located near the intermediate image provided by the focusing lens group and functions to correct the residual chromatic aberrations. The system is characterized by a high numerical aperture (type. greater than 0.

Abstract: An imaging system includes a compound elliptical concentrator having an illumination source at an entry aperture and having an exit aperture directed to project light onto the surface of an object. The compound elliptical concentrator includes first and second reflective surfaces that are arcs of different ellipses. The ellipse that defines the arc of the first reflective surface has one focus that is proximate to an entry end of the second reflective surface. The ellipse that defines the arc of the second reflective surface has a focus that is proximate to the entry end of the first reflective surface. The other foci of the ellipses are at or beyond the exit aperture of the compound elliptical concentrator and are preferably symmetrically aligned with respect to the surface to be imaged. The reflective surfaces are on the opposite sides of a plane of symmetry and are configured such that multiple reflections of extreme rays from the illumination source are deterred.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than that of air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element.

Abstract: A technique for correcting wavefront aberrations introduced by large primary optical elements in portions of the electromagnetic spectrum. The aberrations of the primary element are first transferred to a beacon beam and this aberrated beam is interfered with a reference beam in a holographic medium. These beams are then turned off and a beam from a distant object, containing the same aberrations, is allowed to diffract from the hologram. The diffracted beam from the hologram contains the image of the distant object with aberrations removed. Use of this technique permits the construction of large optical elements inexpensively, since surface tolerances of the elements can be substantially relaxed.

Abstract: In a reflection type angle of view transforming optical apparatus for transforming an angle of view in an image apparatus and so forth, sufficient strength can be provided and process is facilitated by using reflecting mirrors in a wide angle optical system. The reflection type angle of view transforming optical apparatus includes a primary mirror 8 having a reflecting surface provided in an axisymmetric form to reflect incident light 12 as primary reflected light 13, a secondary mirror 10 having a reflecting surface provided in an axisymmetric form about the same axis of rotational symmetry 9 as that of the primary mirror 8, opposed to the primary mirror 8 so as to reflect the primary reflected light 13 and to get secondary reflected light 14 for focusing on a view point, and a transparent case 11 to support the primary mirror 8 and the secondary mirror 10, and transmit the incident light 12.

Abstract: This invention velates to an image displaying apparatus which includes a plurality of image displaying devices for displaying respective display images on display surfaces thereof, reflecting surfaces provided in correspondence to the respective image display devices, each for reflecting a light beam from the corresponding image display device and an optical system for guiding light beams from the plurality of reflecting surfaces to a pupil of an observer.

Abstract: Telescope comprising two or more reflecting elements, wherein a light beam impinging on a first reflecting element leaves through a second reflecting element, in which the shape of the reflecting surface of the second reflecting element is concave. The shape of the reflecting surface of the first reflecting element is concave. An entrance pupil is arranged in the light path in front of the first reflecting element and the first reflecting element images the entrance pupil nearly in the focus of the second reflecting element.

Abstract: Catadioptric projection systems are disclosed for projecting an illuminated region of a reticle onto a corresponding region on a substrate. The systems are preferably used with ultraviolet light sources (e.g., 193 nm). The systems comprise a first imaging system, a concave mirror, and a second imaging system. The first imaging system comprises a single-pass lens group and a double-pass lens group. The single-pass lens group comprises a first negative subgroup, a positive subgroup, and a second negative subgroup. Light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, and reflects from the concave mirror to pass back through the double-pass lens group to form an intermediate image of the illuminated region of the reticle. The light is then directed to the second imaging system that re-images the illuminated region of the reticle on the substrate.

Abstract: A FLIR staring array detector system for imaging an object scene using catadioptric optics has a cold shield efficiency approaching unity. The system provides a full format image of the object scene. The catadioptric optics include reflective objective optics for providing an intermediate image of the object scene and refractive relay optics for providing the full format image. The system further includes a staring detector for receiving the full format image.

Abstract: Catadioptric optical systems are disclosed that comprise, objectwise to imagewise, a positive first lens, a meniscus second lens having a convex face oriented objectwise, a meniscus third lens having a concave face oriented objectwise, and a concave spherical mirror having a concave face oriented objectwise. Light from an object passes through the first through third lenses and reflects from the concave mirror to form an image between the third lens and the concave mirror. The system satisfies the condition .vertline.f.sub.123 .vertline./f>10, where f.sub.123 is the aggregate focal length of the first through third lenses, and f is an overall focal length of the system. The first and second lenses are preferably made of a specified optical material, collectively have a positive refractive power, and fulfill the condition .vertline.f.sub.12 .vertline./.vertline.f'.sub.12 .vertline.>1, where f.sub.12 is the aggregate focal length of the first and second lenses, and f'.sub.

Abstract: The disclosure relates to an LCD projector illumination system that optimizes the illumination through a liquid crystal screen as well as through the aperture of the system's objective, wherein the shape Zr,.beta. of the reflector is described by a set of elementary surfaces dS each of which is associated with a function Z(.rho.), corresponding to a median plane (r,.beta.) to be illuminated, defined by the distance r between the center and the edges of said screen and the angle .beta. between the horizontal plane and this median plane, the inclination of each elementary surface dS being computed by interpolating said functions Z(.rho.) with a function Z(x,y).

Abstract: Magnification correction for small field scanning of large blanks is provided by adding magnification adjusting elements (lenses) to a double pass Wynne-Dyson lens or other type of one-to-one projection lens. The magnification adjusting optical elements includes two pairs of low power lenses, one associated with each of the input and output prisms of a Wynne-Dyson lens. Movement of the magnification adjusting optics provides positive or negative magnification as needed to correct for any expansion or compaction of the blank relative to the reticle (mask) and hence maintain alignment. Further magnification correction is provided by a small velocity relative movement between the reticle and the blank by means of a secondary stage in the scan direction. This corrects for any alignment error in the scan direction and may be used independently of the optical correction technique with any type of projection lens.

Abstract: A head-mounted image display apparatus (HMD) including an ocular optical system, which has an F-number of 1.5 to 3 and enables a flat and clear image to be observed at a view angle of up to 60.degree. or more with substantially no aberration. The HMD has at least two, surfaces and each having a concave surface directed toward the pupil. The two surfaces are disposed so that light rays from an image display device are reflected by the first surface, and the reflected light rays are reflected by the second surface and pass through the first surface to enter an observer's eyeball.

Abstract: A device for accurately positioning the vertex of a secondary mirror (5) off-centered with respect to that of a primary mirror (3) of a telescope (1). The secondary mirror (5) is connected to a support (8). The connection (9) includes two radial and crossed elongate connecting members (10) which extend on either side of the support (8) (along a first direction X--X and a second direction Y--Y) passing through the center (0) of the support, corresponding to the vertex (5A) of the secondary mirror (5). Each of the connecting members (10) is longitudinally rigid and transversely flexible. Each of the connecting members is capable of being controlled, in order to move along its longitudinal extent by an actuation device (11).

Abstract: An ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 .mu.m), comprises a focusing lens group with multiple lens elements that provide high levels of correction of both image aberrations and chromatic variation of aberrations over a selected wavelength band, a field lens group formed from lens elements with at least two different refractive materials, such as silica and a fluoride glass, and a catadioptric group including a concave reflective surface providing most of the focusing power of the system and a thick lens providing primary color correction in combination with the focusing lens group. The field lens group is located near the intermediate image provided by the focusing lens group and functions to correct the residual chromatic aberrations. The system is characterized by a high numerical aperture (typ. greater than 0.

Abstract: An optical apparatus monitors the entire panorama in low resolution and simultaneously monitors a selected portion of the panorama in high resolution. For the panoramic portion of the apparatus, a mirror having a convex surface of revolution with a hole therein is used. The higher resolution part of the apparatus uses a pointing mirror positioned above this hole. The panoramic and higher resolution views are imaged through lenses or optical components onto a detector. The panoramic view is imaged onto the detector as an annulus of light in which either higher or lower elevational angles of the panorama are imaged further away from the detector's center depending upon how the convex mirror is configured. In this way, the resolution of that portion of panorama that is imaged further away from the detector's center is enhanced. The higher resolution view is imaged to the center of the annulus.

Abstract: A wide FOV imaging system (10) includes an objective lens (14), a convergent reflective element (18) positioned proximate an intermediate image (16) formed by the objective lens, and a re-imaging lens (20) for re-imaging the intermediate image. The present invention significantly improves image fidelity while minimizing optical components by utilizing a convergent reflective element proximate the intermediate image to reverse the propagation of aberrations produced by the objective lens (14) to, as a result, significantly cancel or reduce the aberrations contributed by the re-imaging lens.

Abstract: A catadioptric reduction projection optical system having a structure capable of increasing a numerical aperture without increasing the size of a beam splitter and achieves excellent performance of a semiconductor manufacturing apparatus. The catadioptric reduction projection optical system comprises a first partial optical system having a first lens group, the beam splitter, a lens element, and a concave reflecting mirror to form an intermediate image of a first object, a second partial optical system for forming a reduced image of the intermediate image on a second object, the second partial optical system having a second lens group of a positive refracting power and arranged in an optical path between a second object surface and a surface on which the intermediate image is formed, and a third lens group arranged in an optical path between the beam splitter and the third lens group. The first lens group is arranged in an optical path between the first object and the beam splitter.

Abstract: A first partial optical system including a first group of lenses having a positive refractive power, a first concave reflection mirror and a second group of lenses having a positive refractive power, for forming a primary reduced image of an object, a second partial optical system including a second concave reelection mirror and a third group of lenses having a positive refractive power, for further reducing the primary reduced image and refocusing it, and a reflection mirror arranged between the first partial optical system and the second partial optical system, for deflecting a light path are arranged in a sequence as viewed from the object. A good image-forming ability as a projection optical system for fabricating a semiconductor device is attained with a simple construction.

Abstract: The telescope includes at least one primary concave mirror (MI) for receiving an incoming image and relay optics for enlarging the image reflected by the primary mirror. The relay optics comprise a secondary mirror (M2) and a tertiary mirror (M3), each having a central aperture (12, 13) and each being positioned coaxially with the primary mirror (M1). The secondary mirror (M2) receives the image reflected by the primary mirror (M1) through the central aperture (13) of the tertiary mirror (M3). The tertiary mirror (M3), positioned close to the focal plane of the primary mirror (M1), receives the image reflected by the secondary mirror (M2) and reflects that image through the central aperture of the secondary mirror (M2).

Abstract: An optical system including at least one lens and erecting mirrors designed and arranged to give an inherent aperture and field greater in one direction than another direction. By using a low power eyepiece lens it is possible to arrange for a user's eye or eyes to be further behind the eyepiece lens so that the user can wear normal spectacles to correct for eye defects. When a pair of the optical systems is used in a pair of binoculars, it is possible for the exit pupils to be in a form of horizontal slots so the systems do not have to have adjustable spacing to allow for a particular user's eye separation.

Abstract: An optical system is provided for a FLIR mounted in a cylindrical turret ch has five folding mirrors, two doubling as scanning mirrors, numerous lenses with aspherical surfaces and different refractive indices, and a rotatable head mirror. Some of the lenses and mirrors being mounted on remote controlled electrically powered focusing or scanning means.

Abstract: A nonimaging radiant energy device may include a hyperbolically shaped reflective element with a radiant energy inlet and a radiant energy outlet. A convex lens is provided at the radiant energy inlet and a concave lens is provided at the radiant energy outlet. Due to the provision of the lenses and the shape of the walls of the reflective element, the radiant energy incident at the radiant energy inlet within a predetermined angle of acceptance is emitted from the radiant energy outlet exclusively within an acute exit angle. In another embodiment, the radiant energy device may include two interconnected hyperbolically shaped reflective elements with a respective convex lens being provided at each aperture of the device.

Abstract: A beam expander suitable for use with laser machining apparatus comprises a convex paraboloidal surface 7 and a concave paraboloidal surface 8 formed from a single metal element 10. The expander has an optional zoom facility provided by a plane mirror 12, moveable along an input-output axis, for altering the position of an incident beam on the convex surface 7 thereby altering the magnification of the system.

Abstract: A Dyson lens system includes a radiation source, a concave mirror, and a plano-convex lens. There is also incorporated in the system an additional lens that is spaced from the plano-convex lens a large part of the distance from the plano-convex lens to the mirror. A roof prism and a turning prism are provided to conduct radiation from the radiation source to the plano-convex lens and also from the plano-convex lens to an image plane. An image adjustor or compensator is provided between the prisms and either the image plane or an object plane--the latter being disposed between the radiation source and the prisms. An adjustment mechanism is provided to effect highly accurate adjustment of the location of the image, the adjustment mechanism including physical shifting to a slight degree of a portion of one or both prisms.

Abstract: A nonimaging radiant energy device may include a hyperbolically shaped reflective element with a radiant energy inlet and a radiant energy outlet. A convex lens is provided at the radiant energy inlet and a concave lens is provided at the radiant energy outlet. Due to the provision of the lenses and the shape of the walls of the reflective element, the radiant energy incident at the radiant energy inlet within a predetermined angle of acceptance is emitted from the radiant energy outlet exclusively within an acute exit angle. In another embodiment, the radiant energy device may include two interconnected hyperbolically shaped reflective elements with a respective convex lens being provided at each aperture of the device.

Abstract: A binocular reflecting telescope having two Cassegrain or Schmidt-Cassegrain reflecting mirror units having the same aperture and the same focal length; each unit includes a concave primary mirror and a convex secondary mirror provided opposite to each other along each of two parallel first optical axes; the telescope also having two erect real image forming devices each including a combination of place mirrors for guiding a ray of light out of the first optical axis from a point between the primary mirror and the secondary mirror. Two eyepiece units are provided and are rotatable about the optical axes of the light rays guided out of the two erect real image forming devices.

Abstract: A compact wide-view angle image display apparatus which displays an image by using an optical system. A lens unit (L1) is disposed on the optical axis (A1) of an LCD (11). A magnifying reflecting mirror (12) is disposed on an optical axis (A2) perpendicularly intersecting the optical axis (A1). A half-mirror surface (13) is disposed at a tilt on the intersection point of the optical axis (A1) and the optical axis (A2) so that the half-mirror surface (13) reflects a bundle of rays from the LCD (11) to the reflecting mirror (12) and transmits the ray bundle reflected from the reflecting mirror (12). A magnifying reflecting mirror (14) is disposed to face the reflecting mirror (12).

Abstract: A concentric optical system usable as either an imaging optical system or an ocular optical system, which has an F-number of 1.5 to 3 and enables a flat and clear image to be photographed or observed at a view angle of up to 60.degree. or more with substantially no aberration. The concentric optical system includes at least two semitransparent reflecting surfaces (2) and (3) each having a center of curvature disposed in the vicinity of a pupil (1) and a concave surface directed toward the pupil. The semitransparent reflecting surfaces are disposed so that each semitransparent reflecting surface passes each particular bundle of light rays at least once and reflects them at least once, thereby providing a flat image surface (4).

Abstract: An optical display system in which an image is projected onto a combiner surface at a significant bending angle effectively compensates asymmetric aberrations, including quadratic, linear and constant binodal astigmatism components and both linear and constant coma components. Forward and rear optical lens relay groups are positioned between an image generator and the combiner surface. The two relay groups are independently decentered and angularly tilted to increase the degrees of freedom available for aberration compensation. The lenses included in the two relay groups are also designed to compensate for chromatic aberrations, thus allowing for the use of a broad bandwidth combiner and an operating bandwidth that encompasses substantially the full visible spectrum. The reduction in aberrations makes possible a significant increase in the system's field of view.

Abstract: A lightweight telescopic lens of monolithic construction is revealed that corporates additional refractive and reflective curved surfaces to produce all the optical functions performed by an ordinary telescope. A pair of such lenses may be mounted in an eyeglass frame to yield a telescope that can be worn like a pair of eyeglasses, thus affording superior image stability as well as free the user's hands. Minor modifications involving the use of several menisci of a different index of refraction from that of the core lens can be made to achieve achromatism of emergent light from achromatic input light. The entire core lens can also be shaped into a meniscus to take advantage of the principle of total internal reflection, thereby increasing the light-gathering aperture while at the same time rendering the lens even more compact and lightweight.

Abstract: To develop a design form for a Cassegrain-type telescope with spherical primary and secondary mirrors, which is well-corrected for chromatic aberration as well as for geometrical aberrations including spherical aberration, coma and astigmatism, the designer begins with a "starting design form" for a conventional Cassegrain-type telescope with spherical primary and secondary mirrors, and then modifies the "starting design form" by:(a) positioning lens elements of a corrector lens group along an optic axis inside the front focal plane of the spherical primary mirror, where the lens elements of the corrector lens group are made of optical materials that enable a desired degree of correction for chromatic aberration to be achieved;(b) providing a reflective coating on a central portion of the back surface of the rear-most lens element of the corrector lens group, which replaces the secondary mirror of the "starting design form" and becomes the secondary mirror of the telescope;(c) locating the entrance pupil of t

Abstract: A Newtonian binocular telescope (20), which is readily adaptable to popular telescope mounts, such as the Dobsonian mount (76), and which includes two primary mirrors (42a, 42b), and two secondary mirrors (32a, 32b), in a single tube (21) of either solid wall or open frame construction. The single tube (21) allows central secondary optical axes (34a, 34b) to be disposed in laterally and longitudinally separate parallel relation to one another so as to form a comfortable interocular axis (36) between them. Both telescopes' oculars (50a, 50b) are conveniently disposed adjacent an ocular wall (22) on a side of tube (21) nearest one of the telescopes. The viewer is provided easy access (91a, 91b and 92a, 92b) to primary alignment means (87a, 87b), which may be used to merge images between telescopes.

Abstract: An afocal optical system is formed by a paraboroid mirror and an optical element having a stereographic projection characteristics which is defined by the following equation:hi'=2.multidot.f.multidot.tan (.theta.i/2)where hi' is a height of a light beam, leaving the optical element, taken from the optical axis or a heigh of an image taken from the optical axis, f is a focal length of the optical element and .theta.i is an angle of incidence with respect to the optical element. The focal point of the optical element coincide with that of the first paraboroid mirror. Thus, a compact afocal optical system which satisfies hi'=m.multidot.hi is manufactured at low costs.

Abstract: A high-resolution synthetic aperture, adaptive optics system includes an imaging system having a plurality of optical elements including at least a primary mirror which is a section of the aperture to be synthesized, and a detector for receiving the radiation collected by the primary mirror; and a device for rotating the primary mirror section through a number of angular positions about the aperture being synthesized to obtain a plurality of component images of an object, at least one from each of the positions; a device for sensing distortion of an incident wavefront; and a device responsive to distortions of the wavefront for locally adjusting at least one of the optical elements to correct distortions in the wavefront.

Abstract: An imaging system (10) for a Head-Mounted Display (HMD) comprises a projection screen (22) integrally formed with a headgear structure of the HMD. An image source is projected onto the projection screen (22) as an intermediate image. An optical sub-system (24), such as a lens, re-images the intermediate image to form a virtual image as viewed by a user's eye (26). The present invention provides improved imaging while reducing the weight and manufacturing cost of the HMD. In accordance with another aspect of the present invention, an optical spatial filter (28) is utilized in an HMD imaging system to remove unwanted image artifacts, and increase the depth of focus of an intermediate projected image.

Abstract: An image observation device includes a two-dimensional image display element, a relay optical system for forming a real image of an image displayed on the two-dimensional image display element, an eyepiece optical system for forming a magnified image of the real image and bending the optical axis, and a supporting member for supporting the eyepiece optical system to be located directly before the eyes of the user. This arrangement makes it possible to provide the image observation device which is small in size and high in magnification for observation.

Abstract: An afocal optical system is formed by a paraboroid mirror and an optical element having a stereographic projection characteristics which is defined by the following equation:hi'=2.multidot.f.multidot.tan(.theta.i/2)where hi' is a height of a light beam, leaving the optical element, taken from the optical axis or a heigh of an image taken from the optical axis, f is a focal length of the optical element and .theta.i is an angle of incidence with respect to the optical element. The focal point of the optical element coincide with that of the first paraboroid mirror. Thus, a compact afocal optical system which satisfies hi'=m.multidot.hi is manufactured at low costs.

Abstract: An optical system (10) includes a three mirror anastigmat telescope (12) and imager optics (14). The imager optics (14) provide narrow and wide field of view staring of the viewed scene. The optical system is positioned in a turret assembly (50) and folded to provide a sensor. The sensor includes an output laser beam generator (90). The telescope (12) is shared by the infrared system and the laser (90) to provide a simplistic and compact turret arrangement (50) which is well suited for aircraft targeting and designation purposes.

Abstract: A reduction projection system characterized by large numerical aperture has an unobscured optical path without the need to resort to truncated lens elements and provides locations for field and aperture stops. The system includes a first lens group, a first double-pass component group, a first concave mirror, a second lens group, a second double-pass component group, a second concave mirror, and a third lens group. The light encounters the first double-pass component group before and after it encounters the first concave mirror. Similarly, the light encounters the second double-pass component group before and after it encounters the second concave mirror. Together, the first lens group, the first double-pass component group, the first concave mirror, and the second lens group form an intermediate reduced image of the object at an intermediate image plane. The second double-pass component group, the second concave mirror, and the third lens group form a further reduced image at an image plane.

Abstract: A concentrating lens has a receiving surface that is substantially spherical and a rear or reflecting surface that is substantially hyperbolic. The reflected radiation is directed to a focusing concavity in the receiving surface from which the resultant concentrated beam emerges, substantially in a direction that is opposite to the direction of the impinging radiation.

Abstract: In accordance with the present invention, a BOE-corrected, off-axis image forming apparatus is disclosed. The apparatus has a first stage with a primary reflective element disposed to reflect light incident from an entrance pupil of the apparatus and form a real image at an intermediate image plane, and a second stage located off-axis with respect to the first stage. The second stage is defined by a secondary reflective and/or refractive assembly which re-images light from the intermediate image plane to a final image plane. A binary optical element (BOE), which has higher-order optical characteristics for providing aspheric correction but extremely low optical power, is provided in one of the stages for correcting aberrations introduced by the other optical elements in the apparatus. The BOE contributes no more than about 3% of the optical power provided by the stage which contains the BOE.

Abstract: An optical reimager (20) is formed by combining a two-element optical relay (24) with a single-element imager objective (22). The relay (24) comprises a refractive element (26) that is used twice and a mirror (28) that provides a real stop. The reimager can be made diffraction-limited by configuring the mirror with an aspheric surface to correct spherical aberration introduced by both the refractive element (26) and the objective (22), and configuring the objective with an aspheric surface to correct non-spherical aberrations (principally astigmatism and coma). The reimager (20) is described in connection with a thermal imaging application requiring telecentricity and a remote entrance pupil.