Abstract: The present optical system (20) provides an all-reflective vehicle rear vision optical system. A planar mirror (22), acting like a conventional vehicle rearview mirror, would be positioned to receive a beam. The beam would be provided by an image erecting assembly (30) which, in turn, would reflect the beam into a three-mirror anastigmat telescope (24, 26 and 28) to provide rearward image beam to the first planar mirror and in turn, to the exit pupil (25). The optical system provides a 2X magnification at a wide field of view which substantially eliminates blind spots.

Abstract: An all-reflective three-mirror afocal system has a negative power primary (12), positive power secondary (14), and positive power tertiary (16) mirror which form an afocal reimaging optical system. The system is capable of imaging very wide fields of view at low magnification and may be utilized in pilotage, navigation, driving or the like operations.

Abstract: An all-reflective optical three-mirror system has a negative power primary (12), positive power secondary (14), and positive power tertiary (16) mirror which form a focal reimaging optical system. The system is capable of imaging very wide fields of view and may be utilized in pilotage, navigation, driving or the like operations while providing substantially complete detector cold shielding.

Abstract: The present optical system provides an all-reflective boresight transfer system. A reflective mechanism receives and reflects energy from an incoming collimated beam to focus it upon a target surface. The target surface absorbs and subsequently re-emits as a longer wavelength most of the energy and also reflects a small portion of the energy such that an exit beam comprised of both the re-emitted and reflected energy is reflected through the reflecting mechanism and re-collimated by the reflecting mechanism. The exit beam has the same direction as the input beam except that it is deviated by 180.degree. and laterally offset from the input beam so that the exit beam may be used as a reference for determining or aligning the line of sight of other optical systems.

Abstract: The present optical system provides an all-reflective afocal reimaging system. A reflective system receives, by means of an entrance aperture, and reflects radiation or light through the system such that the radiation or light is imaged and recollimated as it is reflected through the system. The radiation or light exits at an exit aperture which is an image of the entrance aperture. High quality images of both the collimated scene and reimaged aperture are formed by the optical system. Embodiments are shown by which the optical system can be used as an optical derotation device by the inclusion of two planar mirrors located near the entrance and exit apertures.

Abstract: Illumination, heating and/or damage to baffles (114) and other structures (112) of a telescope (110) during cleaning of its mirrors (116, 118) by a laser beam (128) is avoided by directing the= laser beam from a source (130) outside of the telescope through its entrance aperture (126) and to a reflector (146). The reflector is secured to an already existing telescope shutter (120) so that the beam can be directed on a return path back from the reflector through the entrance aperture and to the outside of the telescope. Preferably, the cleaning occurs by a Nd:GSGG (neodymium and chromium doped gallium garnet crystal) laser (130) after reflection from the reflector. Cleaning is also obtainable by a laser beam generated by a carbon dioxide laser prior to reflection from the reflector.

Abstract: A helmet mounted display uses a see-through visor holographic combiner to provide, in the normal field of view of a helicopter pilot, a pair of images derived from an image source such as a miniature cathode ray tube. A source of the video display may be an infrared sensor mounted on an external turret underneath the helicopter. The turret rotates in response to helmet movements so that the pilot is continually provided with a dual image from the CRT display which corresponds with the external scene as visible through the visor.

Abstract: An all-reflective multiple field of view optical system has first (10) and second (12) reflecting assemblies sharing a common packaging volume in a single unit which are movable with respect to one another to provide multiple fields of view utilizing a common entrance pupil region (14) and viewing plane (16).

Abstract: The present optical system provides an all-reflective continuous zoom optical system. An imaging mechanism including the tertiary mirror (14) of a three-mirror (10, 12, 14) anastigmat is moved to effect a change in the focal length, field of view, or both of the system.

Abstract: A three-mirror anastigmat system has a plurality of focal lengths, fields of view or both reflected to its focal planes. The system includes a positive power primary mirror (10) and a negative power secondary mirror (12) transmitting an image of an object to be viewed to a plurality of tertiary mirrors (14 and 16) operating at various magnifications. The tertiary mirrors (14 and 16) provide the plurality of images with different or the same focal lengths and fields of view to the plurality of focal planes (22 and 24).

Abstract: A method and apparatus for receiving optical signals is disclosed. The apparatus 10 comprises a primary mirror 14 to create an intermediate image 22 between the primary mirror 14 and a secondary mirror 16. The apparatus 10 further comprises a tertiary mirror 18 in optical communication with the secondary mirror 16.

Abstract: An interferometric spectrometer (20) for determining two-dimensional positional and spectral information of two-dimensional light sources (26) is disclosed. The spectrometer (20) includes a mechanism (28) for splitting a beam source (24) into two beam components (30) and (32). A mechanism (34) and (36) for focusing and centering the pair of beam components (30) and (32) is positioned in the line of projection of the beam components (30) and (32). A mechanism (38) and (40) for reflecting the pair of beam components (30) and (32) is positioned in the line of projection of the two beam components (30) and (32). A detector mechanism (42) for detecting the beam components (30) and (32) is positioned in the line of projection of the two beam components (30) and (32). A mechanism (44) for determining spatial and spectral information of the source (26) is associated with the detector mechanism (42 ).

Abstract: A head-up display for use in a vehicle is provided with a curved combiner which reflects an image from a cathode ray tube (CRT) as collimated rays to a viewing site. A relay lens is positioned between the CRT and the combiner to magnify and transfer the image. The combiner may be a partially-reflecting mirror or holographic optical element or dielectric laminate. Included within the relay lens is a coma-control plate having two-dimensional undulations described mathematically by a two-dimensional power series having odd symmetry in a plane of a tilting of the combiner and even symmetry in the perpendicular dimension. The coma-control plate substantially reduces coma in an image presented for viewing at infinity, the coma being introduced by the curvature and off-axis use of a surface of the combiner.

Abstract: A wavefront sensor (10) for use in determining a phase error of an input beam (16) is disclosed. The wavefront sensor (10) includes mechanisms for obtaining a sample of an input beam (16). A mechanism (18) for splitting the beam (16) into two component beams (46) and (48) is associated with the beam (16). A second mechanism (20) for splitting the two component beams (46) and (48) into four component beams (58), (60), (62) and (64) is associated with the first splitting mechanism (18). A mechanism (26) for detecting the intensity distribution of the four component beams (58), (60), (62) and (64) is associated with the second splitting mechanism (20). A mechanism for determining the phase error of the input beam (16) from the intensity distributions is associated with the detector mechanism (26). Also disclosed is a method for determining the phase error on an input beam (16 ) using the above described wavefront sensor (10).

Abstract: An integrated optic holographic spectrometer (10) for analyzing electromagnetic radiation from a source (12) is disclosed. The holographic spectrometer (10) comprises a substrate (18) having aperture (20) for restricting the receipt of electromagnetic radiation. The spectrometer (10) also includes two optical waveguides (22, 24) for dividing the electromagnetic radiation received through the aperture (20) into at least a first and second portions. A geodesic lens (26) is provided for collimating the first and second portions of the electromagnetic radiation. Finally, the spectrometer (10) includes a linear detector array (28) optically communicating with the geodesic lens (26) to provide an output responsive to the interference between the first and second portions of the electromagnetic radiation received through the aperture (20).

Abstract: A non-relayed optical system is used off-axis in both aperture and field angle relative to an optical axis (32), and employs three reflective lens elements (34, 36, 38). The system is useful for viewing radiation from a distant object, the radiation allowed to enter the system through an opening in a real and accessible entrance pupil (44) that is disposed in front of a concave primary mirror (34). Because the entrance pupil of the system is real and not virtual, the aperture stop of the system is coincident with the entrance pupil, resulting in a significant reduction in beam wander about the front of the optical system. The real entrance pupil of the system also allows the system to be utilized for applications where it is required that the system view distant objects by means of a small viewing port, window or object space scan mirror.

Abstract: Primary mirror 12, secondary mirror 14 and tertiary mirror 16 form an anastigmatic relayed image forming optical system which is off-axis and decentered in both aperture and field angle. The secondary and tertiary mirrors are tilted and decenter relative to the optical axis of the primary mirror to enhance image quality. Additional advantages include compact packaging, easy accessibility to all components, and improved shielding of unwanted out-of-field radiation.

Abstract: There is disclosed an integrated optical design of head-up displays suitable for use in aircraft cockpits and the like. The display system is comprised of a holographic optical element used as the combiner for presenting a direct view of the exterior on which are superimposed image signals generated by a source device such as a cathode ray tube and transmitted to the combiner through an optical system including a relay lens containing tilted and decentered optical elements to compensate for the aberration present in the holographic optical element. There are further disclosed four relay lens design forms particularly suited for use in the design of such holographic head-up displays. The disclosure includes integrated designs in which (a) the holographic element may or may not be constructed with aberrated wavefront and (b) a beam splitter is incorporated for insertion of a stand-by sight, possibly also being tilted for the correction of aberrations.

Abstract: There is disclosed a liquid crystal image projector which is suitable for use as an image source in an aircraft head-up display system. In this application, the projector provides extremely bright and high contrast symbology for the aircraft pilot. More generally, the projector has application wherever a television-type raster and/or calligraphic symbology display is needed. The increase in brightness and contrast ratio is achieved by using a reflector to concentrate light from a light source onto the liquid crystal display cell from whence it is reflected through an optical aperture stop in the reflector to the projecting lens and thence to a viewing surface.