Abstract: The invention concerns a device for micrometric positioning with respect to a frame (1) of an optical support (2) element (3) integrated in a space system, comprising three turrets (4, 5, 6) integral with the frame (1) and, for each turret first means (9 to 12) for adjustment along a first direction, second means (20 to 22) for adjustment along a second direction, third means (30 to 35) for micrometric adjustment along a third direction, and means for locking the support (2) in adjusted position with respect to the frame (1) comprising at least a lock screw and a shim.

Abstract: An apparatus and method of making very small curvature modifications of the reflective surface of a mirror in a printer raster scanning system for bow correction of the scanning beam by gripping edges of the mirror to bend it with a gripping system and applying a very small movement thereto by gross rotation of screw shaft of a differential screw system operatively connected to that gripping system. The screw shaft has two separate fine screw thread patterns of slightly different screw pitches causing gross rotation of the screw shaft to only move the mirror gripping system and its engaged portion of the mirror by micro-meter amounts by automatically subtracting the two slightly different screw pitches from one another, thus providing very small, easily controlled, deformation of the mirror plane for bow correction by non-critical gross rotation of the screw shaft.

Abstract: A method of fabricating glass or other transparent material second surface reflectors for solar energy concentrating systems, with attachment devices affixed to the back of the mirror. The attachment devices are used to attach the reflector to a supporting frame. The silver or other reflecting material that the forms the reflecting surface is removed in a small area so the attachment device can be affixed directly to the glass or other transparent material rather than to one or more layers of reflecting materials and protective coatings. The reflecting surface of a glass mirror is usually protected by one or more layers of protective coating. This results in one or more interfaces between the glass and the adhesive used to affix the attaching device. Each interface can present an area for inconsistent bonding. Removing the reflecting surface and protective coatings thus provides for a stronger bond than might be achieved by attaching the attachment device to the protective coatings.

Abstract: An active mirror has a reflectively coated diaphragm, a mount, and at least one actuator, in which a second diaphragm is connected to the mount, and the actuator is operatively connected to the two diaphragms. The active mirror is symmetrical with respect to a midplane.

Abstract: A durable large stroke deformable mirror. In the illustrative embodiment, the mirror (10') includes a faceplate (12') constructed of a first material, and a backplate (14') constructed of a second material different from the first material. The faceplate (12') is connected to the backplate (14') at an interface (16'), and the backplate (14') is connected to a set of actuators (20') capable of inducing large mirror (10') deflections. In a specific embodiment, the first material is chosen for its excellent optical qualities and the second material is chosen for its flexibility and durability, allowing for large mirror (10') deflections. To ensure the durability of the connection at the interface (16'), the faceplate (12') and the backplate (14') have matching coefficients of thermal expansion. In addition, the interface (16') is placed at the neutral axis of the mirror (10') for reducing stresses at the interface (16').

Abstract: A Light-weight low cost mirror for astronomical purposes and a method of manufacturing said light-weight mirror is disclosed. The light-weight mirror is comprised of an optical plate a backing plate and a core disposed between said optical plate and said backing plate. The core is comprised of a plurality of core strips. Said core strips are assembled in an arrangement wherein the core strips, the optical plate and the backing plate form cavities by the intersection of the core strips with the backing and the optical plate. The cavities are open the outside diameter edge of the mirror. A method is also disclosed for manufacturing the mirror by fusing the core to opposing faces of the optical plate and backing plate. Melt support assemblies are used to support the unfused backing plate and core strips. The unfused assembly is heated to the glass melting temperature to fuse the core to the optical plate and backing plate.

Abstract: A holder improving the optical performance of a reflecting optical member in a projection optical system which projects an image of a pattern formed on a mask onto a photosensitive substrate, and an exposure apparatus having the holder. A support mechanism supports a back surface of the reflecting optical member, which is reverse to a reflecting surface thereof, at at least three points. The support points are positioned on a circumference away from the center of the reflecting surface by a distance at least 0.6 times the distance from the center of the reflecting surface to the outer periphery of the reflecting optical member such that the support points are circumferentially spaced along the circumference at equal intervals. Alternatively, a holding member supports the reflecting optical member and forms a closed chamber in combination with the reflecting optical member.

Abstract: A reflector includes a frame over which is stretched a flexible sheet of reflective material to define a curved reflecting surface of pre-determined geometry. The frame defines arcuate sections portions of which support the sheet and lie on the surface of pre-determined geometry. At least one of the arcuate sections is deformable to displace the respective sheet supporting portion and thereby adjust the tension in the flexible sheet.

Abstract: An array of M.times.N thin film actuated mirrors for use in an optical projection system, the array comprises an active matrix including a substrate and an array of M.times.N connecting terminals and an array of M.times.N actuating structures. Each of the actuating mirror structures includes a first thin film electrode, a barrier member, a thin film electrodisplacive member, a second thin film electrode and an elastic member. In order to improve mirror morphology and improve the adhesivity between thin films, the barrier layer is placed on top of the thin film electrodisplacive layer and the top surface of second thin film layer is ion-damaged by using an ion beam, respectively.

Abstract: A deformable mirror compatible with short wavelength (extreme ultraviolet) radiation that can be precisely controlled to nanometer and subnanometer accuracy is described. Actuators are coupled between a reaction plate and a face plate which has a reflective coating. A control system adjusts the voltage supplied to the actuators; by coordinating the voltages supplied to the actuators, the reflective surface of the mirror can be deformed to correct for dimensional errors in the mirror or to produce a desired contour.

Abstract: A light weight arcuate reflector facet, for a solar concentrator is disclosed, which comprises a thin mirrored glass sheet such as a microsheet, and a backing sheet or substrate, the glass sheet being bonded to the backing sheet, with the backing sheet providing a smooth surface to the glass sheet. A support member or support structure is attached to the backing sheet and maintains the mirrored glass sheet at a desired radius of curvature. The backing sheet is preferably a composite, and according to one embodiment of a fixed focal length light weight reflector facet, the support member is a resin-impregnated fiberglass sheet having a rib structure. In another embodiment of a variable focal length light weight reflector facet, the support member is a mechanical structure comprising a circular support structure having intersecting center support beams positioned diagonally across the circular support structure.

Abstract: An inventive array of M.times.N thin film actuated mirrors includes an active matrix, a passivation layer, an etchant stopping layer, and an array of M.times.N actuating structures. Each of the active matrix includes a substrate, an array of M.times.N MOS transistors, M number of source lines, N number of gate lines, an array of M.times.N connecting terminals and an array of M.times.N levelling members, top of the levelling member being at a same level as that of the connecting terminal. Each of the actuating structures includes a first thin film electrode, an thin film electrodisplacive layer, an elastic layer and a conduit, and has a proximal end and a distal end, the proximal end being divided into a first and a second side portions, wherein the first side portion of the proximal end is located on top of the connecting terminal in the active matrix and the second side portion of the proximal end is located on top of the levelling member in the active matrix.

Abstract: Strut joint assemblies which include built-in off-loading capability or mirror support systems allow a user to minimize the friction developed at the ball joint interface. Each strut joint assembly includes an upper ball joint and a lower ball joint. Each of the ball joints is sealed such that an internal compartment is created which can act essentially as an air spring. By raising the air pressure within these compartments, the load on the ball joint is reduced until the joint separates and air pressure alone carries the entire load. By adjusting the pressure to a value just below the separation pressure, the ball can still maintain contact with the ball socket and carry very little of the actual load. At this pressure, the frictional moment that can be generated by the joint is minimized and is, thus, greatly reduced from the frictional moment developed by a joint which is carrying the full gravity load of the mirror.

Abstract: A dual action support cylinder placed between a support (2) and a load (1) for applying on said load a nominal force of about 400 to 3900N for a low displacement of less than 1 cm, having a body (1) forming a vessel connected to said support (2) and closed on both sides by a cover (11, 12), said covers and body defining a housing with two chambers (32, 33), each sealed by a flexible membrane (36, 39). The two covers (11, 12) are connected to each other by connecting means (16) comprising ties (45) arranged through the body (10) and the covers (11, 12). The body (10) has a cylinder flange (30, 31) placed on either side of a core member (50) and cooperating with a collar (37, 40) for gripping the inner edge of each membrane (36, 39), wherein the movement of the cylinder is guided by metallic membranes.

Abstract: An improved support for a telescope mirror using a system of three bars which are joined at their ends to the back of the mirror with compliant adhesive pads. Preferably, one end is joined to the center of the mirror while the others are joined on the circumference of a circle centered on the center of the mirror. In this preferred embodiment, there is an approximately right triangular relationship between the centers of the bars. The backs of the bars are coupled at their centers to mirror adjusting mechanisms by further compliant pads. The numbers of support points can be increased by coupling further bars or triangles between the circumferential support points of the original three bars and the back of the mirror. Again coupling is provided by compliant adhesive pads. The thickness and size of all pads are controlled to provide stiff support in compression and shear along with resilient support in bending.

Abstract: A small-sized optical reading device for performing the high-speed optical scanning of an object to be read, and for returning light irregularly reflected by the object. In this device, a first reflector element is driven in such a manner as to perform reciprocative rotations or vibrations clockwise and counterclockwise. Further, a medium, on which a bar code, namely, the object is recorded, is scanned by light beams reflected by the first reflector element. The light beams irregularly reflected by the medium are returned to a reflector element array consisting of second reflector elements of a reciprocative vibration reflector. Independent drive signals are provided concurrently to the first reflector element and the reflector element array. The reflecting surface of the first reflector element has a size sufficient to the extent that the entire spotlight caused by a semiconductor laser can be reflected.

Abstract: A mechanism for isostatic fitting of a fragile element, such as a mirror, to a support, generally carried on board a spacecraft, is provided. The mechanism includes three identical connecting devices circumferentially distributed around the optical axis of the mirror. Each device has a flexible blade or plate, whose longitudinal axis is preferably oriented in a direction tangential to a circle centered on the optical axis. The cross-section of the flexible blade decreases progressively from a first end fixed to the support to a second end fixed to the mirror, through a deformable member. The deformable member is adapted to flex in order to permit a relative rotation about a radially oriented axis. The fixtures to the support and the mirror are provided by rods operating only in tension and compression.

Abstract: The control of a mirror's shape, such as for use in large reflecting telescopes, is associated with discrete points so as to avoid incurring constraints and exerting undesirable stress on the reflecting mirror through control unrelated to the mechanical characteristics. Thus, a reflecting mirror is approximated by a non-constrained circular plate having a similar mechanical structure, and an eigenfunction value arithmetic unit calculates values of Bessel-Fourier functions which are eigenfunctions of free vibrations of the circular plate. Using these function values, a mode displacement identification unit approximates a required mirror displacement, which is necessary to correct for wavefront distortion, with a linear combination up to a prescribed mode of vibration of the eigenfunction. A support mechanism command unit controls an actuator so that the value of the linear combination function equals the amount of mirror displacement at a position supported by a reflecting mirror support mechanism.

Abstract: A new adaptive optics system and method of operation, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation:G'=(I-X(X.sup.T X).sup.-1 X.sup.

Abstract: A method and apparatus are provided to allow the operator of a vehicle wishing to change traffic lanes to temporarily scan an angle of the passing lane which is in his or her "blind spot", i.e., an area outside the normal angle of viewing of a conventional flat side rear view mirror. The invention is also useful to divert the headlight reflection from a vehicle in a passing lane out of an operator's eyes. Accomplishment is through temporary pivotal movement of the side mirror to shift the mirror viewing angle from the position at which it had been preset by the operator for normal driving.

Abstract: The present invention is a viewing assembly that can selectively create optical compound corrections in the images reflected from the viewing assembly. The viewing assembly includes a reflective surface coupled to a supporting body in such a manner that the reflective surface conforms to the contour of the supporting body. The contour of the supporting body is selectively altered by the viewer of the viewing assembly, thereby changing the shape of the reflective surface and creating desired optical corrections in the viewed reflected images.

Abstract: The present invention is a viewing assembly that can selectively create optical compound corrections in the images reflected from the viewing assembly. The viewing assembly includes a reflective surface coupled to a supporting body in such a manner that the reflective surface conforms to the contour of the supporting body. The contour of the supporting body can then be selectively altered by the viewer of the viewing assembly, thereby changing the shape of the reflective surface and creating desired optical corrections in the viewed reflected images.

Abstract: A controllable optical mirror system incorporating a ferro-fluid having a surface which acquires an equilibrium shape in response to a gravitational field, rotational motion, and applied magnetic fields. The magnetic field has a predetermined spatial variation which produces an advantageous optical shape in the ferro-fluid surface.

Abstract: A reflecting mirror support apparatus is characterized in that three reflecting mirror support mechanisms (2) are respectively provided with a supporting structure part (10) fixed on the mirror cell (102), a lever (7) installed on the supporting structure part (10) rotatably around a first axis which extends parallel to the circumferential direction of the reflecting mirror (1), a rotating part (6) installed on the lever (6) rotatably around a second axis constituting an axis of the lever (6) and around third and fourth axes which intersect the second axis and a connecting part to be installed on the rotating part (4,5,6) and to be fixed on the reflecting mirror (1) and that the three reflecting mirror support mechanisms (2) are respectively fixed in such a manner that they will not be displaced in the first axis direction or the second axis direction.

Abstract: An array of M.times.N thin film actuated mirrors comprises a switching matrix, an array of M.times.N pairs of supporting members, and an array of M.times.N actuating structures, wherein the active matrix includes a substrate and a first, a second and a third conduction line patterns printed on top thereof, and each of the actuating structures is provided with a pair of actuators and a pair of gate actuators. With the presence of the gate actuators in each of the actuating structures in conjunction with the first, the second and the third conduction line patterns on the switching matrix, it is possible to eliminate the use of transistors in the array of M.times.N thin film actuated mirrors.

Abstract: An array of electrodisplacive actuators is prepared by first forming on an electrodisplacive ceramic wafer a plurality of regularly spaced vertically directional trenches running parallel to each other, followed by forming a first conductive metallic layer thereon. A multiplicity of regularly spaced horizontally directional trenches running parallel to each other and running normal to the plurality of vertically directional trenches is then formed on the thus prepared ceramic wafer. A ceramic block having a top and a bottom surfaces is then formed by bonding together two ceramic wafers, prepared using the above described procedures. The top and the bottom surfaces of the ceramic block are removed until the first conductive metallic layer is exposed, and then a series of regularly spaced vertically directional grooves is formed thereon. Finally, a second conductive metallic layer is deposited on a bottom and side surfaces of each of the grooves to thereby form the array of electrodisplacive actuators.

Abstract: The present invention is intended to obtain a reflector supporting mechanism capable of preventing axial deviation of a sleeve of a reflector side and a socket of a supporting mechanism side and facilitating remounting of the reflector supporting mechanism from/onto the reflector. The reflector supporting mechanism according to the present invention comprises a cylindrical sleeve, a socket which is provided with a flange and crowned at its tapered side part and adapted to come in contact with the sleeve by a side contact point and a flange part, and a universal joint provided on the socket.

Abstract: A reflectance modulator (10) includes a reflective plate (16) with a plurality of slots (18) forming a slot matrix of square portions (20). Side wall plates (22) are each slidingly received within a slot (18) forming a plurality of black body cavities (24) facing incoming radiation. Actuators (28) support the reflective plate (16) with respect to an object surface (12) and are energizable to modify the spacing of plate (16) from the surface (12) changing depth of the cavities (24) and reflectance of radiation.

Abstract: A deformable mirror device which includes a deformable face plate, a backing plate spaced from the deformable face plate, and at least one axially movable actuator which extends between the face plate and the backing plate. The actuator is fixed adjacent a first end to the backing plate and adjacent a second end, which is opposed to the first end, to the deformable face plate in a kinematic joint by reason of which no forces are transmitted in an ideal mating of the two components. At least a portion of the actuator may be disconnected and removed from the first end, and replaced by another actuator. The kinematic joint includes a high temperature, permanent, joint and a pair of spaced apart, low temperature, temporary joints. The high temperature joint is defined by a ball segment affixed to the deformable face plate as by frit. One of the low temperature joints is defined by an epoxy connection between the actuator at its first end and the backing plate.

Abstract: The present invention is a viewing assembly that can selectively create optical compound corrections in the images reflected from the viewing assembly. The viewing assembly includes a reflective surface coupled to a supporting body in such a manner that the reflective surface conforms to the contour of the supporting body. The contour of the supporting body can then be selectively altered by the viewer of the viewing assembly, thereby changing the shape of the reflective surface and creating desired optical corrections in the viewed reflected images.

Abstract: A reflector which is formed of three or more of reflector modules (called stacks) arranged in arrays and bonded to each other, the stacks being arranged to average the distribution of thermal deformations thereof in terms of inhomogeneity among the stacks in average coefficient of linear expansion, thereby suppressing deformation and deterioration of image-forming performance quality of the reflector under varying temperature conditions. The stacks are arranged in order of the magnitude of values of average coefficients of linear expansion possessed by said stacks so that a thermal deformation pattern produced is a relatively simple pattern, there is provided a reflector device in which correction of thermal deformation can be made by a few actuators.

Abstract: A deformable mirror system comprises a reflective face sheet, substrate, positioned behind the face sheet, having actuator bore holes extending entirely through the substrate. Actuator assemblies for deforming the face sheet are positioned in a different ones of the actuator bore holes and are bonded to both a back surface of the face sheet and to the substrate. The actuator assemblies each comprise a tile bonded to a back surface of the substrate to close a distal end of the actuator bore hole and an actuator bonded to the tiles, extending through the bore hole, and bonded to the face sheet near a proximal end of the bore hole. These assemblies can then be individually removed by destroying the adhesive quality of these bonds.

Abstract: A double reflector is described which comprises two spaced apart primary mirrors oriented toward a common focus. The optical system further comprises two separate secondary deflector mirrors as well as tertiary deflector mirrors for beam concentration on a common focus. Both the primary mirrors and the secondary deflector mirrors are so-called off-axis reflectors, i.e. their surface represent surface sectors of a hypothetical big aspherical mirror body. As surface sectors of a hypothetical big hyperbolic mirror, the primary mirrors are inclined at an angle with respect to the common optical axis and each disposed at a given spacing from the same in such manner that the inner marginal rays of the incident radiation which are closest to the optical axis, will converge.

Abstract: An adjustable beam splitter includes a pentaprism type reflector unit including a housing, a splitter mirror positioned in the housing for transmitting a portion of an input energy beam and for reflecting a portion of the input energy beam, and a reflective mirror mounted within the housing for directing the reflected portion of the input energy beam at a fixed angle to the input energy beam regardless of the angle of incidence of the input energy beam to the splitter mirror and regardless of manufacturing tolerances of the splitter mirror. Translation of the reflected portion of the input energy beam is reduced and the split ratio adjusted by rotating the pentaprism type unit about a line corresponding to the intersection of a plane containing the splitter mirror and a plane containing the reflective mirror.

Abstract: A telescope mirror assembly includes a space frame; a deformable mirror body; a plurality of spaced supporting elements bonded to the mirror body by an adhesive; a fastening assembly for releasably securing each supporting element to the space frame for combining the mirror body and the space frame into a self-supporting construction; piezoelements interposed between each supporting element and the space frame for selectively imparting by the piezoelements a pressing or pulling force to a portion of the mirror body for moving such portion toward or away from the space frame.

Abstract: A tilting kinematic mount having optics which may be precisely positioned so as to direct light or other energy to a number of measuring devices. Optic carrying tilting plates, interleaved with stationary plates are moved by linear actuators. An arrangement of balls and grooves establishes positioning of the tilting plates in a kinematic mount relative to the stationary plates, thus achieving the precise rearrangement of optical elements relative to a central axis and the redirection of the energy beam onto the sensing devices.

Abstract: An improved laser correction mirror (10) for correcting aberrations in a laser beam wavefront having a rectangular mirror body (12) with a plurality of legs (14, 16, 18, 20, 22, 24, 26, 28) arranged into opposing pairs (34, 36, 38, 40) along the long sides (30, 32) of the mirror body (12). Vector force pairs (49, 50, 52, 54) are applied by adjustment mechanisms (42, 44, 46, 48) between members of the opposing pairs (34, 36, 38, 40) for bending a reflective surface 13 of the mirror body 12 into a shape defining a function which can be used to correct for comatic aberrations.

Abstract: An actuator device of particular use in changing the configuration of a deformable mirror faceplate includes an electrically deformable actuator confined between a grounded electrode disposed on a front surface of a support and an end cap of a tensioning unit which further includes an elongated tensioning element secured to the end cap and passing through a central opening of the actuator and a passage in the support with a free end portion thereof extending beyond the other surface of the support. A tensioning assembly for imposing a preloading force on the actuator includes an externally threaded sleeve surrounding and secured to the free end portion of the tensioning element, and an internally threaded nut meshing with the sleeve and acting on the support.

Abstract: Described herein is a reflector which is formed of three or more of reflector modules (called stacks in followings) arranged in arrays and bonded to each other the stacks being arranged to average the distribution of thermal deformations thereof in terms of inhomogeneity among the stacks in average coefficient of linear expansion, thereby suppressing deformation and deterioration of image-forming performance quality of the reflector under varying temperature conditions. Since the stacks are arranged in order of the magnitude of values of average coefficients of linear expansion possessed by said stacks so that a thermal deformation pattern produced is a relatively simple pattern, there is provided a reflector device in which correction of thermal deformation can be made by a few actuators.

Abstract: Disclosed is a method and apparatus for electrostatically shaping a membrane suitable for use in antennas or the like, comprising an electrically conductive thin membrane where the periphery of said membrane is free to move in at least one direction, a first charge on the electrically conductive thin membrane to electrostatically stiffen the membrane, a second charge which shapes the electrostatically stiffened thin membrane and a restraint for limiting the movement of at least one point of the thin membrane relative to the second charge. Also disclosed is a method and apparatus for adaptively controlling the shape of the thin membrane by sensing the shape of the membrane and selectively controlling the first and second charge to achieve a desired performance characteristic of the membrane.

Abstract: A procedure for supplying a mirror (22), such as the mirror of an astronomical telescope (60), with holographic optical elements (38), suitable for use with an active mirror alignment system such as a Hartman optical mirror alignment system, is accomplished by constructing each holographic optical element as a separate unitary structure of a transparent substrate (56) with zone plate features. The zone plate features include the channels (64) and ridges (66) of a fragmentary portion of a zone plate etched into a face (58) of the substrate. The substrate is mounted to the mirror by placing the etched face of the holographic optical element in contact with the reflecting surface (68) of the mirror. An adhesive (70) may be applied around the perimeter of the substrate to secure the substrate in its position upon the mirror.

Abstract: The sensitivity model of a complex optical system obtained by linear ray tracing is used to compute a control gain matrix by imposing the mathematical condition for minimizing the total wavefront error at the optical system's exit pupil. The most recent deformations or error states of the controlled segments or optical surfaces of the system are then assembled as an error vector, and the error vector is transformed by the control gain matrix to produce the exact control variables which will minimize the total wavefront error at the exit pupil of the optical system. These exact control variables are then applied to the actuators controlling the various optical surfaces in the system, causing the immediate reduction in total wavefront error observed at the exit pupil of the optical system.

Abstract: A system for correcting wavefront distortion includes an eight channel deformable mirror 11 attached to a two-axis, tip/tilt mount 12. The deformable mirror 11 reflects an incoming telescopic wavefront 10 onto a beamsplitter 14. The beamsplitter 14 divides the reflected telescopic wavefront 13 into two separate beams 15, 20. The beam 20 reflected by the beamsplitter 14 may be used for experimentation and measurement. The beam 15 transmitted by the beamsplitter 14 is directed toward a modified Hartmann-Shack wavefront sensor 16. The modified Hartmann-Shack sensor 16 detects the slope of the wavefront at several locations across this transmitted beam 15 and provides analog signals 17 representing these slopes to a series of actuator drive circuits 18. The actuator drive circuits 18 provide excitation signals 19 to actuators 22, 30 on the deformable mirror 11 and the two-axis, tip/tilt mount 12.

Abstract: An actuator device of particular use in changing the configuration of a deformable mirror faceplate includes an electrically deformable actuator confined between a back surface of a support and a nut that is threaded onto a threaded end portion of elongated tensioning element that has an end cap secured to the other end portion. The tensioning element passes through a central opening of the actuator and a passage in the support. A spring is interposed between the front surface of the support and the end cap. Tightening of the nut imparts causes the spring to exert its restoring force on the actuator to subject the same to a mechanical preload pressure. Another nut may be threaded onto the threaded end portion of the tensioning element to be received in a corresponding recess of the support and pre-deform the spring in the absence of the actuator.

Abstract: In a deformable mirror having a mirror face plate and a plurality of axially movable piezoelectric actuators for controlling the contour thereof, an improvement is provided by which a pneumatic pre-load assembly is inserted between the face plate and the actuators. The assembly includes a core, having apertures therethrough, with a plurality of mirror surface contour posts passing separately through said apertures and a diaphragm plate which is mounted between the face plate and the core and spaced from such face plate but in contact with such core and one end of the posts. A rear plate is mounted to the other end of such posts and in spaced proximity with the core, which core, together with the diaphragm plate and the rear plate, define a cavity therebetween. The posts are aligned with actuators on the other side of the rear plate. Gas is applied to such cavity to bring the posts and the rear plate into contact with their associated actuators so as to pre-load them.

Abstract: A main mirror for a reflecting telescope comprises plurality of individual polygonal reflecting elements (1 to 11) and positioning and adjusting elements (12) connected thereto. Prior art main mirrors of this type have a poor capacity for transmitting ponint images and for modulation and are unsuitable for use in the infrared region, because the positioning and adjustment elements, in particular the measurement sensors arranged in the region of the separating lignes between the individual polygonal reflecting elements (1 to 11) emit interfering thermal radiation. Furthermore, the polygonal reflecting elements (1 to 11) of prior art main mirrors (20) are expensive to manufacture.

Abstract: The mirror support arrangement of the invention takes up force components in the azimuthal axis of the primary mirror of a telescope as well as moments about the mirror axis at the location where they are developed. Although forces of this kind cannot occur in earthbound telescopes, a rapid rotation about several axes can generate such moments especially when the mirror is driven in a mount having three orthogonal drive axes. A hydraulic lateral support acts at several points on the rear side of the mirror. This support is realized in the form of a V-support. The lateral V-support can take up all lateral forces within the V-angle.

Abstract: A mirror support apparatus for a reflecting telescope employs an astatic lever with a counterweight to provide radial support and drives the lever parallel to the telescope axis to provide axial support. The axial supporting force is delivered to the mirror through a load cell which is located between the end of the lever and the mirror directly or indirectly (through a linking rod or diaphragms). The load cell therefore detects the entire axial force applied, and does not detect radial components even if the mirror shifts in relation to its cell. The lever is driven in the axial directing through a spring which helps achieve fine adjustment. A damping device can be added to damp vibrations. The counterweight can be attached to the lever by another spring to compensate for lever bending effects. This apparatus is capable of providing both axial and radial supporting forces with the high precision required by very large, thin telescope mirrors.

Abstract: A method and apparatus are disclosed for edge phasing an array of segments in a segmented primary telescope mirror using white light from a far field source and starting with the inner edge of each segment in the first ring of segments. The segments are individually phased for zero piston and tilt error with respect to the edge of a reference surface in the open center position of the telescope mirror, and proceeding from ring to ring by edge phasing one edge of each segment in each subsequent ring with an edge of a segment in a preceding ring that has been edge phased. After edge phasing of all segments in the telesope mirror array has been completed, full surface phasing can be achieved using a conventional Shack-Hartmann technique followed by finding the RMS best fit for each segment of the mirror array.

Abstract: A segmented mirror control system comprises an array of structural elements (e.g. mirrors) which can be actively positioned to maintain an accurate pre-determined overall shape. The present invention is "active" and so may be characterized as an Active Segmented Mirror Control "ASMC". The segments of a mirror or the reflecting panels, in for example, a radiotelescope, may be continually adjusted with ASMC to provide an accurate reflecting mirror of very large diameter even when disturbed by external forces. ASMC is a closed loop control system. That is, an array of sensors is first used to measure differential position errors. This data is then processed to determine position actuator commands. Finally, these commands are used to move the segments until the sensors are nulled and the desired shape is obtained.