Abstract: An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 12°, and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15°. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 &mgr;m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 &mgr;m. Each of the six reflecting surfaces has an aspheric departure of less than 16.0 &mgr;m.

Abstract: An improved optical apparatus and system for producing a three-dimensional real image of an object. The apparatus includes a support member, a first concave reflective surface affixed to the support member and having an associated focal length, and a second concave reflective surface affixed to the support member. The first concave reflective surface and the second concave reflective surface are placed in substantially fixed spatial relationship to each other to define an acute angle so that when the object is appropriately placed further than the focal length of the first concave reflective surface, the apparatus produces a three-dimensional real image of the object.

Abstract: A catoptric reduction projection optical system (5) is provided with a first catoptric optical system (10) that images an object (R) in first (object) plane (OP) into a second plane (12) and forming an intermediate image (II) therein, and a second catoptric optical system (20) that images the intermediate image in the second plane onto a third (image) plane (IP), thereby forming a reduced image of the object in the first (object) plane onto the third (image) plane. The first catoptric optical system comprises a first mirror pair comprising two reflective mirrors (M1, M2). The second catoptric optical system comprises a second mirror pair comprising a convex mirror (M3) and a concave mirror (M4). The system also preferably satisfied a number of design conditions.

Abstract: A mirror projection system for use in a step-and-scan lithographic projection apparatus in which a mask pattern is repetitively scan-imaged on a number of areas of a substrate by means of a beam of EUV radiation having a circular segment-shaped cross-section. The projection system, which is easier to manufacture at lower cost than a projection system with six or more imaging mirrors, has only five imaging mirrors with a good numerical aperture and an acceptable image-ringfield width. An EUV lithographic projection apparatus provided with the new projection system has a wafer throughput which is approximately 50% higher than that of an apparatus provided with a six-mirror projection system. Moreover, such a lithographic projection has a compact construction.

Abstract: A rear view dual mirror assembly comprises a convex mirror on the front and a plane mirror on the reverse side. Whole assembly rotates 360 degrees and tilts/pivots on a fixed base, and is mounted on top of a computer monitor, or on the side of the monitor, using a two sided adhesive foam pad attached to the base. The plane mirror also rotates in its housing, and is used as a vanity mirror, and the convex wide angle mirror is used to achieve the best way to stay aware of your surroundings.

Abstract: Condensers having a mirror with a diffraction grating in projection lithography using extreme ultra-violet significantly enhances critical dimension control. The diffraction grating has the effect of smoothing the illumination at the camera's entrance pupil with minimum light loss. Modeling suggests that critical dimension control for 100 nm features can be improved from 3 nm to less than about 0.5 nm.

Abstract: The optical system provided with a first optical part disposed most adjacent to the object side, the optical part having three or more optical surfaces, of which at least one is a reflecting surface, and an aperture stop disposed more adjacent to the image side than the first optical part, wherein when the spacing from the first optical surface to the third optical surface as counted from the object side of the first optical part is defined as D and the spacing from the first optical surface to the entrance pupil at an azimuth &xgr; degrees is defined as X(&xgr;), the following condition is satisfied: (X(0)+X(90))/2<D. The specification also discloses an optical apparatus provided with such optical system.

Abstract: An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 9°, and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14°. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 &mgr;m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 &mgr;m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 &mgr;m.

Abstract: A reduction objective, a projection exposure apparatus with a reduction objective, and a method of use thereof are disclosed. The reduction objective comprises four (primary, secondary, tertiary, and quaternary) mirrors in centered arrangement with respect to an optical axis. The primary mirror is a convex mirror and the second mirror has a positive angular magnification. The reduction objective has an obscuration-free light path and is suitable for annular field scanning operation, such as is used in soft X-ray, i.e. and EUV and UV, lithography.

Abstract: An electromagnetic radiation collecting and condensing optical system includes a plurality of cascaded concave paraboloid reflectors and a plurality of electromagnetic radiation or light sources which radiate light energy onto the concave reflectors in such manner that the energy from each source is combined by the reflectors into an output target, such as the end of a single core optical fiber.

Abstract: A large, low cost and high quality optical telescope system (1) includes a segmented primary mirror (2) having a plurality of spherical mirror segments (3) arranged in a non-spherical shape (4), a parabolic shape in the disclosed embodiment, so that the rays incident upon the individual spherical mirror segments stay separated at an exit pupil (5) of the system, allowing for correction of aberrations. A discontinuous pupil corrector in the form of a segmented mirror (7) having a plurality of aspheric correction terms in it, is located at the exit pupil for correction of aberrations introduced from respective ones of the plurality of spherical mirror segments of the primary mirror. The discontinuous pupil corrector preferably is a segmented deformable mirror. The telescope system and related method can achieve diffraction limited performance for very large systems. The disclosed embodiment is a 35 meter aperture, deployable space telescope system.

Abstract: In a method and device for removing light by absorption, undesired light is guided by a light entrance aperture into a hollow body having a light-absorbing inner surface. The light which is directed into the hollow body falls onto the reflection surface of a reflector. The reflection surface is configured and positioned in such a way that the light which is reflected back from the reflection surface is not reflected in itself, that only a minor amount of said light does not reach the outside as scattered light via the light entrance aperture and that a substantial amount of the light reaches the inside of the hollow body where it is absorbed. The invention finds particular use in an electronic recording device for point and line elimination of a recording material with a laser beam, wherein an undesired secondary beam is absorbed according to the inventive method in order to avoid disturbing retroreflections.

Abstract: A catoptric reduction projection optical system (5) is provided with a first catoptric optical system (10) that images an object (R) in first (object) plane (OP) into a second plane (12) and forming an intermediate image (II) therein, and a second catoptric optical system (20) that images the intermediate image in the second plane onto a third (image) plane (IP), thereby forming a reduced image of the object in the first (object) plane onto the third (image) plane. The first catoptric optical system comprises a first mirror pair comprising two reflective mirrors (M1, M2). The second catoptric optical system comprises a second mirror pair comprising a convex mirror (M3) and a concave mirror (M4). The system also preferably satisfied a number of design conditions.

Abstract: To freely adjust the angle of the light incident on a workpiece in a light irradiation part for oblique irradiation of the workpiece with light without needing to move a large light irradiation part, on the exit side of a collimation lens or a collimation mirror, in a light irradiation part, there is a flat mirror which is moved in the direction in which the length of the optical path of the irradiation light is changed, such that its angle is changed with respect to the optical axis, and at the same time, the center of an area to be irradiated by reflection of the flat mirror essentially does not move. Thus, the angle of the light incident in the workpiece can be changed. Furthermore, by changing the angle of the collimation mirror with reference to the optical axis and by moving the collimation mirror in the direction in which the length of the optical path of the irradiation light is changed, the angle of the light incident in the workpiece can be changed without using a flat mirror.

Abstract: A mask pattern is repetitively scan-imaged on a number of areas of a substrate by means of a beam of EUV radiation having a circular segment-shaped cross-section. This system, which is easier to manufacture at lower cost than a projection system with six or more imaging mirrors, has only five imaging mirrors with a good numerical aperture and an acceptable image-ringfield width. An EUV lithographic projection apparatus provided with the new projection system has a wafer throughput which is approximately 50% higher than that of an apparatus provided with a six-mirror projection system. Moreover, it has a compact construction.

Abstract: An illumination source or condenser used to project the image of a reticle onto a photosensitive substrate used in photolithography having a first reflective fly's eye, faceted mirror, or mirror array with predeterminedly positioned facets or elements and a second reflective fly's eye, faceted mirror, or mirror array having predeterminedly positioned facets or elements for creating a desired radiant intensity, pupil fill, or angular distribution. A source of extreme ultraviolet electromagnetic radiation is provided to a first fly's eye or mirror array with arcuate shaped facets or elements. The arcuate shaped facets or elements are positioned to create an image of the source at corresponding facet in a second reflective fly's eye or mirror array. A desired shape and irradiance together with a desired radiant intensity, pupil fill, or angular distribution is obtained. An arcuate illumination field or image is formed with high efficiency in a compact package.

Abstract: An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receive a chief ray at an incidence angle of less than substantially 9°, and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14°. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 &mgr;m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 &mgr;m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 &mgr;m.

Abstract: An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 12°, and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15°. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 &mgr;m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 &mgr;m. Each of the six reflecting surfaces has an aspheric departure of less than 16.0 &mgr;m.

Abstract: A catoptric reduction projection optical system (100), a projection exposure apparatus (EX) and a method using same. The catoptric reduction projection optical system is capable of forming a reduced magnification image of an object present on a first surface (R) onto a third surface W. The system includes a first catoptric optical system (10) capable of forming an intermediate image of the object onto a second surface (IM) and comprises a first mirror pair having a first reflective mirror (M1) and a second reflective mirror (M2).

Abstract: The invention is directed to a four-mirror catoptric projection system for extreme ultraviolet (EUV) lithography to transfer a pattern from a reflective reticle to a wafer substrate. In order along the light path followed by light from the reticle to the wafer substrate, the system includes a dominantly hyperbolic convex mirror, a dominantly elliptical concave mirror, spherical convex mirror, and spherical concave mirror. The reticle and wafer substrate are positioned along the system's optical axis on opposite sides of the mirrors. The hyperbolic and elliptical mirrors are positioned on the same side of the system's optical axis as the reticle, and are relatively large in diameter as they are positioned on the high magnification side of the system. The hyperbolic and elliptical mirrors are relatively far off the optical axis and hence they have significant aspherical components in their curvatures.

Abstract: The invention provides a reflector device and a reflector system for mounting to a vehicle having front and rear seats to allow a person in the front seat to view an infant in a rearwardly facing safety seat attached to the rear seat. The reflector system includes a pair of reflector devices of which one may be in accordance with the invention. The reflector device in accordance with the invention is mountable upright on a back of the rear seat and includes a mounting assembly and a reflector with a forwardly-facing reflecting surface pivotally connected to the mounting assembly so as to be pivotable in three-dimensions. The reflector device is preferably mounted to one side of the infant and has an upward extent below the rear window of the vehicle so as not to obstruct a driver's view through the rear window and to not present a hazard to the infant.

Abstract: Condensers having a mirror with a diffraction grating in projection lithography using extreme ultra-violet significantly enhances critical dimension control. The diffraction grating has the effect of smoothing the illumination at the camera's entrance pupil with minimum light loss. Modeling suggests that critical dimension control for 100 nm features can be improved from 3 nm to less than about 0.5 nm.

Abstract: A planetary astrographic telescope of the Cassegrain type having a concave paraboloidal primary mirror and a convex secondary mirror located in the spherical zone between the primary mirror and said primary mirror's focal point. The spherical secondary mirror receives the light reflected from the primary mirror. The secondary mirror, in turn, reflects such light through an aperture in the primary mirror to a focal plane located behind the primary mirror. The spherical secondary mirror and its holder are in combination sized to be not more than twenty percent of the diameter of the primary mirror and positioned in the spherical zone of light reflected from the paraboloidal primary mirror. One embodiment of the present invention is a tube containing the concave paraboloidal primary mirror and convex spherical secondary mirror with said tube attached to and supported on a mount at a height above a support surface.

Abstract: An irradiance redistribution guide (IRG) for providing from a radiation source having a nonuniform irradiation distribution, a predetermined irradiance distribution over a predetermined target area spaced away from the IRG, includes a tubular reflective inner surface disposed between an entrance aperture and an exit aperture. The reflective inner surface has a varying cross-sectional radius. The profile of the cross-sectional radius is defined by a spline function that is uniquely determined by a plurality of knots. The IRG, when used in conjunction with a high-power solar concentrator, is advantageous in materials processing that requires high irradiance level that is uniformly distributed over an area spaced away from the exit aperture by a working distance.

Abstract: A back scattering collector, comprising: a first spherical reflective surface; a second spherical reflective surface having an annular form defining a central aperture; a refractive element, the first and second reflective surfaces and the refractive element being aligned along an optical axis; a light excitation source for illuminating a volume for analysis; the first and second reflective surfaces having respective diameters which reflect light rays back scattered from the volume at least three times between the first and second reflective surfaces, a last one of the at least three refections directing the light rays through the refractive element; and, a photo detector, the refractive element focusing the light reflected light rays onto the photo detector. The second reflective surface can be formed on the convex side of a plano-convex lens, the refractive element being formed by a central portion of the lens. The distance between the reflective surfaces is adjustable.

Abstract: An all-refelctive optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six refelecting surfaces has an aspheric departure of less than 16.0 .mu.m.

Abstract: The present invention is directed to an optical system for measurement of a three dimensional device. The optical system is designed and configured to meet telecentric and f-.theta. requirements. The system employs primary and secondary mirrors operating in conjunction with a tertiary deflector mounted on a pivot. Light from a light source produces a beam which is deflected off the deflector and the secondary and primary reflectors respectively. The beam is then transmitted to the surface of the object to be measured. Deflection of the tertiary deflector on the pivot results in scanning of the light beam across the surface of the object to be measured.

Abstract: A corrector mirror folds the optical path between the objective and relay portions of a three-mirror anastigmat. The corrector mirror is a non-powered mirror having a nominally flat but higher order aspheric surface. By placing the corrector mirror between the objective portion and an intermediate image formed by the objective portion, the field offset of the anastigmat can be significantly increased. A large field offset makes the off-axis anastigmat ideal for use with an on-axis dewar for infrared imaging applications.

Abstract: A reflector assembly is provided for efficiently collecting and forming the electromagnetic radiation from a radiation source into a desired beam pattern. The reflector assembly uses a smaller non-symmetrical generally convex reflector and a larger non-symmetrical generally concave reflector. The generally convex reflector intercepts a large fraction of light emitted by the source that would otherwise escape without interacting with the assembly and redirects this light onto the generally concave reflector for eventual inclusion in the beam.

Abstract: A system and method for wide angle imaging create a high resolution image using a convex primary mirror concentrically positioned relative to a concave secondary mirror and one or more detectors spherically juxtaposed. The radii of the primary and secondary mirrors are related by the square of the "golden ratio" to reduce low order aberrations. A fiber optic faceplate coupled to each detector corrects field curvature of the image which may then be detected with a conventional flat detector, such as a CCD camera.

Abstract: An integrally formed optical element includes an incident surface into which light flux from an object enters, a plurality of reflecting curved surfaces decentered one to the other from which the light flux entered from the incident surface is reflected and an emergent surface from which the light flux from the reflecting curved surfaces is emitted, wherein an antireflection film is applied onto the incident surface and the emergent surface, and wherein the light flux emitted from the emergent surface forms an image.

Abstract: An all reflective ring field projection optic system for use in scanning photolithography used in the manufacture of semiconductor wafers. The projection optics are designed for wavelengths in the extreme ultraviolet ranging from 11 to 13 nm to provide an arcuate image field for a reduction step and scan photolithography system. A sequence or configuration of mirrors from the long conjugate end to the short conjugate end consists of a convex, concave, convex, and concave mirror with an aperture stop being formed at or near the second convex mirror. This sequence of mirror powers provides a relatively large image field size while maintaining a relatively compact reticle wafer distance of less than 900 mm. The projection optics form an instantaneous annual field of up to 50 mm.times.2 mm at the wafer, permitting scanning to cover a field on a wafer of at least 50 mm.times.50 mm, greatly increasing throughput. The optical projection system can print features as small as 0.05 microns.

Abstract: A reflective optical system includes, in traveling order of light, a correction plate having an aspherical surface and a reflecting mirror for concentrating the light. An image is formed out of an optical path between the correction plate and the reflecting mirror.

Abstract: A scanner transmits a generally collimated beam of radiation such that the beam rotates about an axis to form a conical scanning pattern. The scanner comprises a concave parabolic reflector having a geometric axis and a focus, a rotation mechanism for effecting rotation of the concave parabolic reflector about a rotation axis which is angularly offset with respect to the geometric axis of the concave parabolic reflector, an opening formed in the concave parabolic reflector proximate the rotation axis thereof, and a convex parabolic reflector disposed along the rotation axis of the concave parabolic reflector and having a focus which is approximately co-located with the focus of the concave parabolic reflector.

Abstract: A large aperture light-weight space borne telescope is provided which may be launched by a relatively small launch vehicle. A 6 to 8 meter primary telescope composed of, e.g., 30 segments arranged in two concentric rings is provided. Supplemental outer mirror segments are stowed behind and substantially perpendicular to the main mirror which is usable in the absence of supplemental mirror deployment. Deployment of outer mirrors segments provides a large aperture telescope with a large field of view. Other deployable components include a secondary mirror, a bus, deployable with respect to the optics portion, and one or more sun shade sheets or panels.

Abstract: A laser beam condensing device which can be manufactured at low cost by using reflecting mirrors which can be machined at low cost. The device is capable of condensing a laser beam to a high energy density while eliminating any optical path difference, even if the optical axis of the incident beam strays. This device includes a first and a second reflecting mirror. An incident laser beam is deflected by these mirrors in the same direction. One of the two mirrors is a toroidal mirror, while the other is a spherical, cylindrical or toroidal reflecting mirror. The mirror surfaces of the two reflecting mirrors are machined so that the second reflecting mirror can cancel out any wave front aberrations of the laser beam reflected by the first reflecting mirror.

Abstract: A reflector assembly is provided for efficiently collecting and forming the electromagnetic radiation from a radiation source into a desired beam pattern. The reflector assembly uses a smaller non-symmetrical generally convex reflector and a larger non-symmetrical generally concave reflector. The generally convex reflector intercepts a large fraction of light emitted by the source that would otherwise escape without interacting with the assembly and redirects this light onto the generally concave reflector for eventual inclusion in the beam.

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: A wide angle large reflective unobscured system includes a primary reflective element for receiving a broad range of energy, a secondary reflective element for reflecting the energy from the primary reflective element to reimage a virtual entrance pupil at a real aperture stop. A beamsplitter element is provided for reflecting a first portion of the energy, such as visible energy, to a first tertiary reflective mirror, while transmitting a second portion of the energy, such as IR light, to a second tertiary reflector. Each tertiary reflector is capable of focusing the received energies to dual focal planes wherein a compact detector array assembly can convert the images to electronic signals.

Abstract: The light radiation beam emitted by a source of finite dimension, integrated in a transparent plate or in contact therewith, is initially reflected inside the plate by a first surface located on the side of the plate (3) which is more remote from the source. The reflected light rays pass through plate and are again reflected by a second surface having micro projections and then directed outwardly, according to a micro-telescope arrangement.

Abstract: A wide-angle side mirror device with a mirror box having a front and a rear, and first and second side walls. An object window is disposed in the first side wall of the mirror box. An observation window is disposed in the second wall of the mirror box. An object mirror having a curved shape which is concave in horizontal cross section and convex in vertical cross section is disposed to face out the object window and diagonally rearwards. An observation mirror is disposed in the mirror box to reflect a mirror image from the object mirror through the observation window. The object mirror preferably has a doughnut or drum shape, and more preferably has a degree of curvature in horizontal cross section approximately the same as a degree of curvature in vertical cross section. The observation mirror is preferably a flat mirror. The device has a wide field of view and allows the driver of a vehicle to view road conditions at acute angle intersections from the driver's seat.

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: A back mirror has plural mirror surface areas of different curvatures disposed side by side or plural mirror surface areas disposed side by side to form discontinuous planes. The back mirror includes a dividing line having a light diffusion effect formed along a border portion of the plural mirror surface areas. The dividing line may be formed by projections and depressions having a light diffusion effect which are formed on at least one of a transparent substrate, reflecting film and a transparent thin film formed on the reflecting film.

Abstract: The invention provides an imaging spectrometer that provides a wide field-of-view camera and spectrometer for spectral imaging of a large two-dimensional area of the Earth's surface from an orbiting satellite or airplane. The wide field-of-view camera fore-optics includes spherical optical elements arranged monocentrically. The spectrometer includes an all-reflective coupling design that transfers the curved optical image to one or more compact imaging spectrometers. The spectrometers preferably comprise a spherical convex holographic grating and associated reflective optics for dispersing a collimated optical beam into its spectral components and focusing the spectral image onto a planar detector array. The instrument described herein is designed to operate in a "pushbroom" fashion, that is, the forward motion of the satellite or airplane generates the spatial dimension of the resulting image.

Abstract: A mirror optical system includes a main mirror and a sub-mirror which are arranged to oppose each other, and a plurality of columns for coupling the main mirror to the sub-mirror. The main mirror, the sub-mirror, and the columns are constituted by members consisting of the same material, for example, a ceramic material, which has a very small linear expansion coefficient.

Abstract: A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.

Abstract: An optical assembly using a centrally-obscured catadioptric optical objece that provides two different focal planes using the same set of optics. Both optical paths share the same optic axis and common line-of-sight. One focal plane is optimized for use with a high performance GEN II image intensifier tube, and the other is used for either laser receiver or emitter devices.

Abstract: A high efficiency, high performance full color projection system. The system includes a one-to-one relay and a refractive projection lens system. The one-to-one relay combines the outputs from two different spectral image sources, such as blue and red image sources. The refractive projection lens further combines the output from a third spectral image source, such as a green image source, with the combined images from the other two image sources relayed through the one-to-one relay to produce a single output. The one-to-one relay includes three modules, a spherical primary module, a spherical secondary module and a spectral combining module. The refractive projection lens system includes a beam combiner and a projection optics.

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: A concentric optical system usable as either an imaging optical system or an ocular optical system, which enables a clear image to be obtained at a field angle of up to about 90.degree. and with a pupil diameter of up to about 10 millimeters with substantially no chromatic aberration. The concentric optical system includes a first optical component having a first semitransparent reflecting surface (2), and a second optical component having a second semitransparent reflecting surface (3). The first and second semitransparent reflecting surfaces (2 and 3) have respective centers of curvature disposed at approximately the same position (1). The first and second optical components are different in dispersion from each other.