Abstract: A compact, optically fast catadioptric imager. In one embodiment, the catadioptric imager of this invention includes a first group of optical elements optically disposed to receive electromagnetic radiation from an object and having positive optical power, a second group of optical elements, optically disposed between the first group of optical elements and an image plane, having at least one optical surface and having positive optical power, a third group of optical elements, optically disposed between the object and the second group of optical elements, having at least one optical surface and having negative optical power, a fourth group of optical elements substantially centered along an optical axis of said second group of optical elements and having negative optical power, and a fifth group of optical elements having positive optical power.

Abstract: A reduced size catadioptric inspection system employing a catadioptric objective and immersion substance is disclosed. The objective may be employed with light energy having a wavelength in the range of approximately 190 nanometers through the infrared light range, and can provide numerical apertures in excess of 0.9. Elements are less than 100 millimeters in diameter and may fit within a standard microscope. The objective comprises a focusing lens group, a field lens, a Mangin mirror arrangement, and an immersion substance or liquid between the Mangin mirror arrangement and the specimen. A variable focal length optical system for use with the objective in the catadioptric inspection system is also disclosed.

Abstract: A lighting assembly topology that utilizes spectrum controlling materials to render the illumination compatible with night vision imaging systems. The lighting assembly can be used as either a general illumination source or can be used as a backlight for a transmissive display such as a liquid crystal display. The lighting assembly makes use of spectral filtering which is both transmissive and absorptive for specific spectral regions. The exit port of the lighting assembly is completely filtered with a red and near infrared reflective filter. The absorption of the near infrared spectrum to which NVIS are sensitive is reflected by the typical near infrared reflective filter covering the exit port and absorbed within the material lining the housing of the lighting assembly.

Abstract: A system for multiple mode imaging is disclosed. The catadioptric system has an NA greater than 0.65, and preferably greater than 0.9, highly corrected for low and high order monochromatic aberrations. The system employs unique illumination entrances and optics to collect reflected, diffracted, and scattered light over a range of angles. Multiple imaging modes are possible by varying the illumination geometry and apertures at the pupil plane. Illumination can enter the catadioptric optical system using an auxiliary beamsplitter or mirror, or through the catadioptric elements at any angle from 0 to 85 degrees from vertical. The system may employ a relayed pupil plane, used to select different imaging modes, provide simultaneous operation of different imaging modes, Fourier filtering, and other pupil shaping operations.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: An optical system projecting onto an image plane an object that is disposed at infinity by an intermediate image. The optical system includes a front group and a relay optic, each including a plurality of lenses, the intermediate image disposed between the front group and the relay optic. The optical system being configured as the object lying at infinity with at least two switchable and/or zoomable fields of view, the fields of view being imaged into the image plane. The front group including at least three lenses successively disposed towards the image plane. A first one of the lenses including of Ge, at least a second of the lenses including of ZnSe, and at least a third of the lenses including of either MgF2, CaF2 or MgO.

Abstract: A reduced size catadioptric inspection system employing a catadioptric objective and immersion substance is disclosed. The objective may be employed with light energy having a wavelength in the range of approximately 190 nanometers through the infrared light range, and can provide numerical apertures in excess of 0.9. Elements are less than 100 millimeters in diameter and may fit within a standard microscope. The objective comprises a focusing lens group, a field lens, a Mangin mirror arrangement, and an immersion substance or liquid between the Mangin mirror arrangement and the specimen. A variable focal length optical system for use with the objective in the catadioptric inspection system is also disclosed.

Abstract: An image forming system and lens system configured to simultaneously image light at the short wave infrared region (SWIR) and the near infrared region (NIR).

Abstract: A common-aperture, multispectral device uses a folded beamsplitter to simultaneously image near infrared (NIR) and long wave infrared (LWIR) spectral bands. The folded-path optical design makes the sensor extremely compact and lightweight without compromising the F/# or field of view. The design is split into two channels; a NIR channel and a LWIR channel. A Zinc Sulfide environmental window provides the input to the device. The input first is split into the two channels via a Germanium (Ge) beam-splitter. For the NIR Channel, the input is focused directly onto a faceplate through a series of optics. For the LWIR Channel, the input is focused onto the Ge window via a folded design including a first Ge lens, a fold mirror, and then a second Ge lens. From the faceplate of the NIR channel and the Ge window of the LWIR channel, the input is then processed by respective focal planes.

Abstract: A lithographic projection apparatus includes a grazing incidence collector. The grazing incidence collector is made up of several reflectors. In order to reduce the amount of heat on the collector, the reflectors are coated. The reflector at the exterior of the collector has an infrared radiating layer on the outside. The inner reflectors are coated with an EUV reflective layer on the outside.

Abstract: A compact, optically fast catadioptric imager. In one embodiment, the catadioptric imager of this invention includes a first group of optical elements optically disposed to receive electromagnetic radiation from an object and having positive optical power, a second group of optical elements, optically disposed between the first group of optical elements and an image plane, having at least one optical surface and having positive optical power, a third group of optical elements, optically disposed between the object and the second group of optical elements, having at least one optical surface and having negative optical power, a fourth group of optical elements substantially centered along an optical axis of said second group of optical elements and having negative optical power, and a fifth group of optical elements having positive optical power.

Abstract: A zoom lens system is disclosed. The zoom lens system forms a final image of an object and a first intermediate real image between the object and the final image. The zoom lens system includes a first optical unit located between the object and the first intermediate real image. The first optical unit comprises at least one optical subunit which is moved to change the size (magnification) of the first intermediate real image. The zoom lens system also includes a second optical unit located between the first intermediate real image and the final image, at least a portion of which is moved to change the size (magnification) of the final image. The zoom lens system provides a wide zoom range of focal lengths with continuous zooming between the focal lengths.

Abstract: An imaging device includes a refractive imager lying in an optical path, and optionally a telescope that directs the optical path to the refractive imager. The refractive imager includes a first lens group that forms an intermediate image of a scene on the optical path, wherein the first lens group includes a first-lens-group positive-power lens, and a first-lens-group negative-power lens. A second lens group relays the intermediate image to a final image surface on the optical path, wherein the second lens group includes a second-lens-group positive-power lens, and a second-lens-group negative-power lens. A third lens group may be selectively inserted into the optical path between the first lens group and the second lens group and selectively removed from the optical path. The third lens group includes a third-lens-group positive-power lens, and a third-lens-group negative-power lens.

Abstract: Apparatus and methods are disclosed for forming plasma generated EUV light source optical elements, e.g., reflectors comprising MLM stacks employing various binary layer materials and capping layer(s) including single and binary capping layers for utilization in plasma generated EUV light source chambers, particularly where the plasma source material is reactive with one or more of the MLM materials.

Abstract: Systems and methods for improved correction of intrinsic birefringence are provided. Two pairs of optical elements correct for intrinsic birefringence of optical materials. A combination of design criteria for the set of optical elements, including refractive power type, intrinsic birefringence signs, and crystal axis rotation, is used to correct for intrinsic birefringence.

Abstract: An ultraviolet imaging system includes at least two negative lens elements, and at least two positive lens elements. The ultraviolet imaging system satisfies the following conditions: ?3<f(i=330)/r1<?0.5??(1) 65<? (ALL)??(2) 0<?(i=330) (P)??(i=330) (N)<10??(3) wherein f(i=330) designates the focal length of the entire ultraviolet imaging system with respect to a wavelength “i” of 330 nm (base wavelength); r1 designates the radius of curvature of the object-side surface of the most object-side lens element; ? (ALL) designates a reciprocal of a dispersion value, with respect to the d-line, of the glass material of all of the lens elements; ?(i=330) (P) designates the reciprocal of the dispersion value, for the positive lens elements, with respect to the wavelength of 330 nm; and ?(i=330) (N) designates the reciprocal of the dispersion value, for the negative lens elements, with respect to the wavelength of 330 nm.

Abstract: A DUV-capable dry objective for microscopes comprises lens groups made of quartz glass, fluorite, and in some cases also lithium fluoride. It possesses a DUV focus for a DUV wavelength region ?DUV±??, where ??=8 nm, and additionally a parfocal IR focus for an IR wavelength ?IR, where 760 nm??IR?920 nm. For that purpose, the penultimate element is of concave configuration on both sides, and its object-side outer radius is much smaller than its image-side outer radius. The DUV objective is IR autofocus-capable.

Abstract: A system for multiple mode imaging is disclosed. The catadioptric system has an NA greater than 0.65, and preferably greater than 0.9, highly corrected for low and high order monochromatic aberrations. The system employs unique illumination entrances and optics to collect reflected, diffracted, and scattered light over a range of angles. Multiple imaging modes are possible by varying the illumination geometry and apertures at the pupil plane. Illumination can enter the catadioptric optical sytems using an auxiliary beamsplitter or mirror, or through the catadioptric elements at any angle from 0 to 85 degrees from vertical. The system may employ a relayed pupil plane, used to select different imaging modes, provide simultaneous operation of different imaging modes, Fourier filtering, and other pupil shaping operations.

Abstract: A zoom lens assembly (10) compensates optically, as opposed to mechanically, for changes in temperature. In a preferred embodiment a difference in focus between WFOV and NFOV zoom lens positions, over temperature, is minimized such that any actual shift in focus falls within the depth of focus of the zoom lens assembly. The zoom lens assembly has, along an optical axis, first and third lens elements (12,16) that are made from a first material and that have a positive power, a second lens element (14) interposed between the first and third lens elements and movable along the optical axis between a WFOV and NFOV position. The second lens element has a negative power and is made of a second material. The materials are selected such that a change in refractive index for a change in temperature of the first material is less than a change in refractive index for a change in temperature of the second material.

Abstract: There is provided a collector for guiding light with a wavelength of ?193 nm onto a plane. The collector includes a first mirror shell for receiving a first ring aperture section of the light and irradiating a first planar ring section of the plane with a first irradiance, and a second mirror shell for receiving a second ring aperture section of the light and irradiating a second planar ring section of the plane with a second irradiance. The first and second mirror shells are rotationally symmetrical and concentrically arranged around a common axis of rotation, the first and second ring aperture sections do not overlap with one another, the first planar ring section substantially abuts the second planar ring section, and the first irradiance is approximately equal to the second irradiance.

Abstract: A device automatically actuated according to UV intensity includes a UV detector generating an electric signal indicative of a UV intensity of a light received thereby; a comparator in communication with the UV detector, receiving the electric signal to compare the UV intensity with a first threshold value, and asserting an actuating signal when the UV intensity is in a predetermined correlation with the first threshold value; and an actuated object in communication with the comparator, actuated to change a state thereof in response to the actuating signal. The actuated object can be an anti-glare rearview mirror, a sunshade curtain, a headlamp, or a transmittance-adjustable window of a vehicle. The actuated object can be a sunshade curtain or a transmittance-adjustable window of a building.

Abstract: An illuminator system (16) for an interior cabin (12) of a vehicle (14) includes a light source (72) and a beam-forming optic (100) that is optically coupled to the light source. The optic (100) forms an illumination pattern (22) that is directed forward of the vehicle (14). A housing (58) supports the beam-forming optic (100) along a roofline (47) and window perimeter (48) of the vehicle (14).

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: There is provided a collector for guiding light with a wavelength of ≦193 nm onto a plane. The collector includes a first mirror shell for receiving a first ring aperture section of the light and irradiating a first planar ring section of the plane with a first irradiance, and a second mirror shell for receiving a second ring aperture section of the light and irradiating a second planar ring section of the plane with a second irradiance. The first and second mirror shells are rotationally symmetrical and concentrically arranged around a common axis of rotation, the first and second ring aperture sections do not overlap with one another, the first planar ring section substantially abuts the second planar ring section, and the first irradiance is approximately equal to the second irradiance.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

Abstract: An image reading apparatus comprises a light source for illuminating an original, an imaging optical system for forming an image of the illuminated original on the focal plane of the system, and a sensor unit arranged in front of the focal plane. At least two infrared cut filters are arranged on the optical path between the light source and the sensor unit. Those infrared cut filters show respective spectral characteristics that are different from each other. The imaging optical system typically comprises a plurality of lenses and the infrared cut filters are arranged on at least two of the respective surfaces of the lenses.

Abstract: An exposure apparatus (PE1) and exposure method for use in photolithographically manufacturing devices such as semiconductor devices, image pickup devices, liquid crystal display devices and thin film magnetic heads. The apparatus is capable of transferring onto a substrate (W) the image of a pattern on a reticle (R) and includes a light source (2) capable of supplying an exposure energy beam (IL) with a wavelength under 200 nm, and an illumination optical system arranged to receive the exposure energy beam from said light source. The illumination optical system is designed to guide the exposure energy beam to the reticle. The apparatus also includes a projection optical system (PL) arranged between the reticle and the substrate. The projection optical system is capable of forming an image of the reticle pattern onto the substrate based on the exposure energy beam passing through the reticle.

Abstract: An infrared blurring array is formed of a substrate having thereon a surface array of blurlets whose foci vary in distance from a nominal focal surface location, and/or whose optical phases at the nominal focal surface location vary, in a pseudorandom but deterministic manner. The substrate may be made of a material transmissive to a waveband of incident infrared energy, and the blurlets are refractive lenslets in the substrate, or the blurlets may be mirrorlets in a reflective substrate. The blurlets are surfaces each defined by a curvature and an axial offset from a nominal focal surface location. At least one, and preferably both, of the curvature and the axial offset of each blurlet is a value that is randomly selected from a set of values defined by a respective distribution, preferably a truncated distribution.

Abstract: An optical system comprising three lens sections, a catadioptric objective lens section, a reimaging lens section and a zoom lens section, which are all aligned along the optical path of the optical system. The reimaging lens section re-images the system pupil such that the re-imaged pupil is accessible separately from any of the lens sections. The reimaging lens section includes an intermediate focus lens group, which is used to create an intermediate focus, a recollimating lens group, which is used to recollimate the light traveling from the intermediate focus lens group, refocusing group to generate the re-image of the pupil. The optical system may also include a beamsplitter, which creates a separated illumination pupil and collection pupil.

Abstract: Light from a pattern of a mask 3 travels through a first imaging optical system K1 to form a primary image I of the mask pattern. Light from the primary image I travels through a center aperture of a main mirror M1 and a lens component L2 to be reflected by a sub-mirror M2, and the light reflected by the sub-mirror M2 travels through the lens component L2 to be reflected by the main mirror M1. The light reflected by the main mirror M1 travels through the lens component L2 and a center aperture of the sub-mirror M2 to form a secondary image of the mask pattern at a reduction ratio on a surface of wafer 9.

Abstract: Condenser system, for use with a ringfield camera in projection lithography, employs quasi grazing-incidence collector mirrors that are coated with a suitable reflective metal such as ruthenium to collect radiation from a discharge source to minimize the effect of contaminant accumulation on the collecting mirrors.

Abstract: A wide field of view infrared zoom lens assembly (16) having a constant F/Number. The wide field of view infrared lens assembly (16) includes a focusing component (33), a collecting component (37), an aperture stop (46), and a diffracting component (41). The focusing component (33) may include a pair of focusing zoom lenses (34, 36). The collecting component (37) may include a first collecting lens (38) and a second collecting lens (40). The focusing component (33) and the collecting component (37) may be formed from high dispersion, low index material. The aperture stop (46) may be mounted to the first collecting lens (38) to maintain a constant F/Number. The diffracting component (41) may include a diffractive surface to correct color aberrations associated with an infrared waveband. The focusing component (33) and the collecting component (37) cooperate with the diffracting component (41) to focus infrared radiation at an image plane (15) of an infrared detector (18).

Abstract: A lens assembly for near infrared comprising two double convex elements separated by two double concave elements. The first element being the most durable, the center elements being the least expensive and the last element having the greatest focussing power.

Abstract: The invention is directed to a catadioptric microlithographic reduction objective having two concave mirrors (21, 23) facing toward each other. The concave mirrors have a symmetrical configuration and a central bore. Lenses (24 to 60) are mounted downstream of the mirrors (21, 23) on the light path toward the image plane (61). Preferably, lenses (15 to 20) are moved at the object end forward into the intermediate space between the mirrors (21, 23) in the region of the central bore. The light path between the concave mirrors can then preferably be free of lenses. The formation of an intermediate image (Z) downstream of the mirrors (21, 23) affords especially good correction possibilities.

Abstract: An optical axis correcting system includes a first afocal optical system, an optical deflector which corrects the deviation of an optical axis of light incident upon the first optical system, a second afocal optical system, and a light convergent optical system. The optical axis correcting system satisfies (1) 3.60<.vertline.fp(I)/fN(I).vertline.<5.30, (2) 1.00<.vertline.fp(II)/fN(II).vertline.<2.41, and (3) 0.12 <r1 (II)/f<0.

Abstract: An infrared afocal lens assembly for providing an observed magnified IR ie scene with a field of view and a substantially less temperature dependent performance. The assembly includes a collecting lens, focusing lens subassembly movable along the optical axis to provide range focus, an intermediate focal plane, an eyepiece lens subassembly, and an aperture stop. A wide field of view lens subassembly may be used on the optical axis. All lenses are made of either GaAs or ZnS, and all lenses are single lenses only.

Abstract: An infrared zoom lens comprises, in order from the subject end to the image end, a positive power first lens group having lens elements less than three, a negative power second lens group having lens elements less than three, a third lens group having a single meniscus lens element with a concave subject side surface, a fourth lens group having a single convex lens element, and a positive power fifth lens group having at least four lens elements which include a convex meniscus lens with a concave image side surface facing directly to an image plane, the second and third lens groups being axially movable in predetermined relation relative to each other and relative to the first, fourth and fifth lens groups which are stationary to vary the zoom ratio of the infrared zoom lens and form a sharp image on the image plane, and satisfies the following conditions:______________________________________ 1.00 < f1/ft -0.40 > f2/ft 0.35 < f5/ft < 0.70 ______________________________________where f.sub.

Abstract: An infrared lens assembly (16, 60 and 80) operative in the near and far infrared wavebands to focus infrared radiation at an image plane (15) of an infrared detector (18). The infrared lens assembly (16, 60 and 80) includes a focusing component (33, 63 and 83), a collecting component (37, 65 and 85) and a diffracting component (41, 67 and 87). The focusing component (33, 63 and 83) and the collecting component (37, 65 and 85) may be formed from high dispersion, low index material. The diffracting component (41, 67 and 87) may be used to correct color aberrations associated with an infrared waveband.

Abstract: An ultra-broadband ultraviolet (UV) catadioptric imaging microscope system with wide-range zoom capability. The microscope system, which comprises a catadioptric lens group and a zooming tube lens group, has high optical resolution in the deep UV wavelengths, continuously adjustable magnification, and a high numerical aperture. The system integrates microscope modules such as objectives, tube lenses and zoom optics to reduce the number of components, and to simplify the system manufacturing process. The preferred embodiment offers excellent image quality across a very broad deep ultraviolet spectral range, combined with an all-refractive zooming tube lens. The zooming tube lens is modified to compensate for higher-order chromatic aberrations that would normally limit performance.

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 infrared afocal lens assembly for providing an observed magnified IR ie scene with a field of view and a substantially less temperature dependent performance. The assembly includes a collecting lens, focusing lens subassembly, an intermediate focal plane, an eyepiece lens subassembly, and an aperture stop. A wide field of view lens subassembly may be used about the focusing lens subassembly. All lenses are made of either GaAs or ZnS, and all lenses are either single lens or doublets.

Abstract: An achrathermalized reimager includes a front objective defining an optical axis and a relay optic arranged on the optical axis downstream of the front objective. The front objective is both achromatic and athermalized and includes precisely one negative lens made of a material selected from the group consisting of ZnSe and ZnS and one positive lens made of chalcogenide glass.

Abstract: An image detection system (10) uses an optical configuration for both image forming and calibration phases of operation. A field lens (20) has an inner portion (36) of a conventional prescription to allow for collection of scene based energy for an opto-electronic approximation of the infrared detail within the afocal field of view by a focal plane array (32). The field lens (20) also has an outer portion (38) that collects far field energy from a scene area (A.sub.I) through a converging point (P.sub.I). The energy collected from the scene area (A.sub.I) is indicative of the average energy level within the scene. The electrical equivalent values of all energy received from the unique area (A.sub.I) is stored in a multidimensional range used for subsequent gain and offset calibration coefficient calculations.

Abstract: An infrared zoom lens assembly (16) operative as either a continuous zoom or a two-position zoom lens. The infrared zoom lens assembly (16) includes a focusing component (33), a collecting component (37) and a diffracting component (41). The focusing component (33) includes a first focusing zoom lens (34) positioned at the same location at the ends of the zoom range and a second focusing zoom lens (36) movably mounted in the infrared zoom lens assembly (16). The diffracting component (41) may be used to correct color aberrations associated with an infrared waveband. The focusing component (33) and the collecting component (37) cooperate with the diffracting component (41) to focus infrared radiation at an image plane (15) of an infrared detector (18).

Abstract: In a multi-lens infrared objective with wide band chromatic correction, more particularly in the spectral range from 1.4 to 5 .mu.m silicon is employed as a material for lenses with a negative focal length. In this respect the lenses consist of materials, which as regards their dispersion curves are selected from three different material group, of which the first material group comprises materials, whose short wave absorption bands are relatively close to the shortest wavelength to be corrected, the second group comprises materials, whose long wave absorption bands are closer to the spectral range to be corrected than the short wave ones and the third group comprises materials, whose relative absorption band positions are between the materials of the first and second groups.

Abstract: The invention relates to an infrared objective (IR objective) with a lens arrangement for the production of an infrared image on a detector element of infrared detector equipment. In this respect it may be a question of a focal plane array (FPA) within a Dewar vessel with an internal cold shield for substantially preventing access of thermal radiation from the surroundings (spurious light fractions). The internal cold shield is placed behind an external uncooled cold shield comprising several staggered external cold diaphragms.

Abstract: An infrared lens assembly (16) having a variable F/Number. The infrared lens assembly (16) includes a focusing component (33), a collecting component (37), an aperture stop (46), and a diffracting component (41). The focusing component (33) may include a first and a second focusing zoom lens (34, 36) movably mounted in the infrared lens assembly (16). The focusing component (33) and the collecting component (37) may be formed from high dispersion, low index material. The aperture stop (46) may be mounted to the second focusing zoom lens (36) to vary the F/Number between a retracted zoom position and an extended zoom position. The diffracting component (41) may include a diffractive surface to correct color aberrations associated with an infrared waveband. The focusing component (33) and the collecting component (37) cooperate with the diffracting component (41) to focus infrared radiation at an image plane (15) of an infrared detector (18).

Abstract: A dual-band optical system 10 preferably for use in the thermal infrared waveband provides initial detection of a target in a first waveband (8-12 .mu.m) having a wide field of view and discriminated target recognition in the second waveband (3-5 .mu.m) at higher magnification and narrow field of view without any field-of-view change mechanism. The system 10 comprises a detector array 11 which is responsive in both wavebands and an optical arrangement 16 with a common objective component 15 for both wavabands. One waveband is transmitted through dichroic beamsplitters 17,18 to the array 11 whereas the other waveband is reflected by the beamsplitters 17,18 and transmitted through a field lens 28 before reaching the array 11. Both wavebands are incident upon a spectrally selective aperture stop 20 providing a large aperture for the low magnification field and a small aperture for the high magnification field.

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.