Abstract: Geometrical characteristics of conic-section-generated offset reflectors are studied in a unified fashion. Some unique geometrical features of the reflector rim constructed from the intersection of the reflector surface and a cone or cylinder are explored in detail. It is found that the intersection curve (rim) of the rotationally generated conic-section reflector surface and a circular cone with its tip at the focal point is always a planar curve and has a circular projection on the focal plane only for the offset parabolic reflector. Furthermore, in this case, the line going through the center of the circle, parallel to the focal axis, and the central axis of the cone do not intersect the reflector surface at the same point. Numerical results are presented to demonstrate some unique features of offset parabolic reflectors.

Abstract: The bandwidth limitation in space fed phased arrays (that results from the use of phase shifters to implement beam steering) is overcome by a lens arrangement in which independent feeds are provided at the focal plane of the lens. Each feed generates a collimated beam in a different spatial direction. Each beam can then be steered about its central position by means of phase shifters, while retaining a substantially improved bandwidth. An algorithm is derived for designing three-dimensional (3D) microwave lenses with line source feeds by stacking a number of identical two-dimensional (2D) parallel-plate, wide-angle constrained lenses into a cylindrical antenna structure. This lens design provides focused beams over a wide range of scan angles in both elevation and azimuth with only small optical aberration. A wide variety of lens designs can be achieved through this algorithm, dependent upon the constraints which are selected for the 2D lens counterpart. For one design, where all the transmission line lengths in the lens are made equal, the phase errors for beam scanning in the plane containing the cylindrical axis of the antenna are less than their broadside values, regardless of scan angle. This permits wide-angle coverage in both elevation and azimuth from a single lens with both good beam and quality and bandwidth.

Abstract: A focal plane photo-detector mosaic array is disclosed in which thin stacked substrate layers extending in planes perpendicular to the focal plane provide closely spaced electrical contact points at the focal plane, and photo-detectors on the focal plane which individually communicate with those contact points are arranged in rows extending diagonally with respect to the planes in which the stacked substrate layers extend.

Abstract: A method for operating a panoramic optical system to produce a shadow or darkened zone on the apex of a curved lens in order to eliminate undesirable optical interference in the region between the curved reflector and the focal plane is disclosed. The claimed method makes possible the accurate prediction of the diameter of the darkened zone around which the reflected image is annularly disposed, for a lens having a reflective surface of a given radius of curvature and for a specific location of the transparent/opaque border relative to the top of the lens. This makes possible the calibration of vertical displacement of an opaque sleeve for quickly and easily establishing a setting which will produce a darkened zone of a standard diameter.

Abstract: An infrared (IR) detector device comprised of a solid state, radiation ha and high resolution monolithic IR focal plane array for imaging applications. The monolithic IR focal plane array has a heterostructure injection scheme that prevents charged-coupled device (CCD) "well filling" by using a heterojunction barrier between the absorber, or detector layer, and the transfer layer. Injection of signal charge into a CCD multiplexer is controlled by establishing a punch through condition between the absorber layer and the CCD channel. The detector layer and the CCD multiplexer are on different planes of the focal plane array.

Abstract: An automatic focusing system for positioning silicon or other wafer within the focal plane of a photolithographic mask projection system. The position of the wafer is measured at a plurality of points and compared to the position of an optical flat located in the focal plane to provide signals for positioning the wafer at the focal plane of the projection system. The system also includes means for changing the contours of the wafer to cause it to lie in a known plane.

Abstract: In the Gaussian approximation, the propagation between any two planes may be represented as the product of a lower triangular matrix times an upper triangular matrix. The matrices themselves, as well as their elements, have an immediate physical meaning. This representation contains the principal plane representation and the focal plane representation as particular cases.

Abstract: Apparatus for maintaining in focus an image formed at the image plane of an optical instrument, notwithstanding random angular movement of the instrument's housing. Such apparatus includes mounting means for angularly decoupling the image-forming element (e.g., a refractive lens) of the optical instrument from the instrument's housing, thereby allowing the image-forming element to move relative to such housing, and means for maintaining the focal plane of the image-forming element substantially parallel to the image plane of the optical instrument during relative angular movement between the image-forming element and the instrument's housing.

Abstract: The imaging reflector arrangement described in this paper forms a very compact antenna design suitable for generating a scanning fan beam for a 12/14-GHz synchronous satellite communicating with points located in the continental United States. A magnified image of a small array is obtained using a Gregorian arrangement of two paraboloids. A filter, placed in the focal plane of the main reflector, eliminates undesirable field components due to the grating lobes of the small array. Because of the filter, the illumination over the main aperture is a smoothed version of the array illumination. Thus, grating lobes are greatly reduced. By properly adjusting the excitation of the various array elements, an antenna with very low side lobes is obtained.

Abstract: An ophthalmological instrument capable of continuously changing the size of an observed image is disclosed. The instrument comprises an image forming optical system for forming a first observed image, a magnification changing optical system for forming a second observed image from said first image and continuously changing the size of said second image and a correction member for correcting the optical length. To continuously change the size of said second image for observation, the magnification changing optical system includes a positive lens group and a negative lens group which are movable relative to each other in the direction of the optical axis. In order to keep constant the positions of the anterior and posterior focal points of the magnification changing optical system, that is, a composite system of the two lens groups, the optical length correction member is movable in association with the movements of the positive and negative lens groups.

Abstract: Two mutually coherent light beams (50, 58) formed, for example, from a single monochromatic light source (32) are directed to a reflecting surface (20) of a rotatable object (18), such as a mirror, where they are reflected into imaging optical lens (10) having a focal plane optically at infinity whereby a series of interference fringes (14) will be formed in the focal plane (12) which will translate linearly thereacross in response to angular rotation of the object. Photodetectors (22, 24) are located adjacent the focal plane to detect the fringe translation and outputs a signal in response thereto which is fed to a signal processor (30) which is adapted to count the number of fringes detected and develop therefrom a measure of the angular rotation and direction of the object.

Abstract: In tracking optical beams from a source, a pointing error signal is derived from photodetecting the field in the receiver focal plane. This error signal is then used in some manner to control a gimballed system that continually points the receiver optics toward the source. When the source field undergoes turbulent transmission, the optical beam is attenuated and scattered, and the field is randomly defocused at the receiver. In this case the pointing error of the tracking system will evolve as a random vector process in time, statistically related to the random scattering, the photodetection process, and the dynamics of the gimballing system. Such vector processes have probability densities that satisfy well-known differential equations. These equations are derived in terms of accepted scattering models and tracking systems, assuming quadranttype error detectors are used in the focal plane. Approximate solutions are obtained and analyzed for typical operating conditions, and the manner in which the degree of scattering degrades the entire pointing operation is shown.

Abstract: A technique for optical non-uniformity correction of a focal plane imagingystem wherein incoming objective scene light rays impinging on each detector in a focal plane array is corrected on a pixel-by-pixel basis by optical correction means from a separate optical source. The optical correction means is comprised of a multiplicative correction means and an additive correction means. The multiplicative correction means is comprised of a responsivity mask positioned on or near the focal plane that provides a multiplicative factor of unity or less to each detector to cause more uniform sensitivity of the detectors. The additive correction means is comprised of the separate optical source that is positioned in a separate optical train and is comprised of an additive optical correction mask aligned with a light source and focusing screen means and image relay that relay the additive optical correction sensitizing illumination onto the focal plane array or the pixel-by-pixel basis. The additive correction may be used alone.

Abstract: Apparatus useful in pattern recognition comprising a two-dimensional lattice array of nodal points, said points being occupied by summing amplifiers having positive and negative input terminals, and output terminals, a corresponding input array of points carrying voltage levels, said points being representative of a two-dimensional array of pixels the pattern of which is to be analyzed, said pattern being a member of a set of patterns characterized by an archetypal pattern, electrical connections from the input array of voltage points via resistors to the inputs of the summing amplifiers, the connections being made in a predetermined pattern and the conductance values of the resistors being set by computational procedures such that a prescribed set of input patterns of pixels is formed into output patterns at the output of the amplifiers that are analysable as to correlation between output array patterns and the archetypal pattern for the prescribed set, and correlation means and discrimination means for analyzing said output patterns.

Abstract: This paper describes a charge-coupled device (CCD) imaging sensor which is being developed to provide high sensitivity and high scan coverage rate for automatic detection in electro-optical, deep-space, satellite-surveillance applications. The visible-spectrum sensor focal plane is a mosaic of 100 x 400 pixel CCD imagers which are operated in the time delay and integration (TDI) mode permitting continuous high-rate scan coverage while integrating target light levels for high sensitivity. The polysilicon gate, front illumi9ated devices have 30 x 30 μm pixels. Room temperature dark current is less than 3 nA/cm and noise levels are 10-20 electrons. Several aligned rows of imaging CCD arrays located on the focal plane in the scan direction provide multiple samples of the field-of-view for automatic MTI detection processing. Five-chip focal planes have been assembled with positional errors of less than 4 μm. The MTI Signal Processor features imager defect removal, parameter estimation, adaptive thresholding, digital delay, and spatial correlation for MTI. This paper includes descriptions of the sensor system, the CCD imager design and characterization, the signal processor, and a summary of test results of the initial sensor system operated on space surveillance telescopes at the GEODSS Experimental Test System, White Sands Missile Range.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: PURPOSE: To make the luminance of a light exit surface high, its luminance uniform and its color balance uniform by opening a light refraction and diffusion plate arrayed with lens elements having lenses holding optical axes in common on both surfaces by paralleling their optical axes. CONSTITUTION: If it is assumed that rays A, B are made incident to the rotary convex face 33a of a lens element 31 at different incident angles, these rays A, B refract and transmit respectively through the lens element 31a. In this case, the rotary convex face 33a is set roughly equal to the focal plane of a rotary convex face 33b, and the face 33b is set roughly equal to the focal plane of the face 33a and therefore two kinds of the rays A, B incident at different incident angles exit at the distributed light having roughly equal opening angles with the centerlines of the distributed light paralleled to the optical axis of the element 31 at the time when they emit from the face 33b of the element 31. COPYRIGHT: (C)1982,JPO&Japio

Abstract: A transmittance-optimized linear Fresnel lens solar concentrator has been developed. The optical performance of the lens has been analytically predicted, using the method of cone optics, to define the radiant flux profile in the focal plane. Also, the optical performance of the lens has been experimentally determined, using a focal plane radiant flux scanner, under actual solar illumination. A brief description of the lens, its predicted performance, and its measured performance is presented.

Abstract: It has been shown theoretically and experimentally that, in the case of extended ground paths under conditions of strong intensity fluctuations when the atmospheric-turbulence-structure parameter is determined based on the half-width of the mean diffraction picture in the lens focal plane, one should take into account the beam-diffraction parameters and laser-source spatial coherence.

Abstract: An optical system for performing a cosine transform on an input RF signal is described. The optical system includes a source for emitting a beam of radiation, and an acoustic-optical modulation device disposed in the path of the beam and functioning to modulate at least two spaced-apart spatial portions of the beam with different signals to produce two modulated beams. A Fourier transfer lens is provided which is disposed in the path of the two modulated beams for combining the two beams, and a detector is disposed in the path of the Fourier transform beam at the focal plane of the Fourier transfer lens.

Abstract: PURPOSE:To ease production and assembling by specifying the constitution of an objective lens system, eyepiece system and erecting lens system CONSTITUTION:All of the objective lens system L1, erecting lens system L2 and eyepiece system L3 are constituted by the same plastic single lenses whose both faces are mutually symmetrical aspherical faces As a result of this, the primary real image of an infinite object point is formed on the 1st focal plane I1 by the objective lens L1, its secondary real image is formed by the 2nd focal plane I2 by the erecting lens L2 and it is observed by the eyepiece L3, whereby the real image system finder optical system being afocal as a whole is constituted Since the peripheral part of the erecting lens L2 does not contribute to the imaging, the plastic lens whose peripheral part is defective may be untillzed as the erecting lens L2, and the non-defective percentage of the plastic lenses becomes higher

Abstract: PURPOSE:To simplify mechanism and speed inspection by using a filter having a light transmission region. CONSTITUTION:A filter 17 having a ring-form light transmission region is disposed on the rear focal plane of an imaging lens 16. As a result of this, the light from a coherent light source 11 transmits through the subject 15 which is rotated by a rotating mechanism 22, after which it forms the Fourier transformation image of the subject 15 on the rear focal plane of the imaging lens 16 and only the light component by the defect of the subject 15 passes through the filter 17 and images as a light spot in correspondence to the position of said defect on the imaging plane 18. Thence, it passes through a pinhole 19 and is converted to the electric signal corresponding to the size of the defect by a photoelectric transducer 20. This signal causes an incoherent light source 14 to light up. Hence, the position and size of the defect of the subject 15 are displayed in a monitor 29 by way of a dichroic mirror 27 and ITV camera 28.

Abstract: It is now widely accepted that the next generation of infrared focal planes will be two-dimensional mosaics of infrared sensing detectors interfaced with charge transfer cells. One form in which these devices is presently being implemented is with hybrid structures using silicon CCDs for charge transfer, and infrared detectors for photon sensing, both being optimized for the desired application. The basic design of the IR/CCD is controlled by the interface requirements, both mechanical and electrical, wherein the response to photon flux is transferred, physically and electrically, from the detector through the input network to end up as charge in a CCD well. The charge is then laterally transferred off the focal plane in multiplex form. Proper design results in negligible loss in signal-to-noise ratio compared to discrete devices. This paper discusses the architecture and the design of the hybrid IR/CCD from the interface point of view, including planar and bump mechanical configurations, and electrical coupling networks. A summary of state of the art will be presented for detectors, CCDs, and IR/CCD focal planes.

Abstract: PURPOSE:To convert light to parallel luminous fluxes efficiently when a light source is placed on the focal plane of a lens by forming its end face into a spherical shape and selecting its length. CONSTITUTION:A semiconductor laser 2 which is a light source is disposed in the focal position of a refractive index distribution type lens 1 of which the end face 11 is worked to a spherical shape of a radius (r). The refractive index (n) (X) at the point of a distance X from the center of the lens 1 is given roughly by n (X)= n0 [1-(gX) ] (where n0 in the equation is the refractive index on the central axis, (g) is the constant intrinsic to each lens). At this time, the luminous fluxes of good parallelism are obtainable by giving the length S of the lens by the eqation S= g tan [n0rg/(n0-n1)] (where, n1 in the equation is the refractive index of the medium of the outside of the lens).

Abstract: Current research on infrared hybrid focal planes is directed toward devices in whichdetection occurs in a p -n junction formed in an intrinsic narrow energy bandyap semi-conductor, and signal processing is accomplished in a Si CCD multiplexer which is electri-cally interfaced to the detector array. A hybrid array such as this, where the detectorformat is a 32 x 32 matrix, has been fabricated. The active material is backside-illumi -nated InAsSb which has been planar processed and fully passivated. The cutoff wavelengthis 4.0 pm at the operating temperature of 77K. The CCD is four phase with a two levelpolysilicon yate structure. The signal input is via direct injection with an option for dcsuppression. Operation of the focal plane in a staring mode that uses dc suppression isdiscussed. Data derived from the video output is presented; this includes responsivity anddetectivity. Off focal plane non -uniformity compensation is also discussed. Displays ofthermal images utilizing processed data from the hybrid focal plane array will be shown.IntroductionA demand for high performance, high density, nigher operating temperature imaging arrayswhich can be produced in quantity exists. In order to address these needs, a "common"detection technology approach has been adopted; this permits a variety of system require-ments to be satisfied with a maximum of overlap in the technology used. This approach usesa hybrid structure that consists of three components: a photovoltaic detector, which isbackside - illuminated through a transparent substrate; a Si CCD multiplexer, which alsoserves to integrate the signal; and an In interconnect technology, which electrically andphysically joins the detector array to the multiplexer.Changes in detector material and CCD multiplexer input cell allow operation in anyportion of the 3 - 12 pm spectral region for both high and low background. Both epitaxialInAsl_xSbx /GaSb and Hgl_xCdxTe /CdTe are under intensive development for use in this commonapproach; the former for applications in the 3 - 5 um spectral band, the latter for bothmid and far IR spectral bands. Details of current detector performance for these systemshas been given elsewhere (1,2). Photocurrent from the detector is injected into an induceddrain FET (which may be the CCD itself if no "front end" signal processing is desired).The signal may then be processed according to the application, including dc suppression,gain reduction, and ac coupling. This paper reports on the construction and imaging with acommon focal plane array that has InAsSb as the detector material. The focal plane geome-try is a 32 x 32 matrix which is operated in a staring mode.Hybrid ComponentsDetectorsDetectors were fabricated from InAsl_XSbx/ GaSb, grown by liquid phase epitaxy withx = 0.11 (lattice matched system). Fabrication of the detectors is a planar process thatuses Be ion implantation with CVD SiO2 as an insulator (3). The spectral response of thesedetectors is from 1.6 (cut -on of the transparent GaSb substrate) to 3.95 um at 77K, with aquantum efficiency of about 80 percent. At this tpemperature the RoA of at least ninetypecent of the 1024 detectors is in excess of 10

Abstract: The adaptor has a corrected auxiliary objective between the eye lens and photocathode. The objective has a variable short focal length. The photocathode is located in the objective focal plane. One of several objectives can be selected by means of a slide, drum or revolver to suit the focal length of the microscope. The auxiliary objective or objective can be adjusted along the optical axis of the photocathode. The advantage lies in providing the user with the best magnification for the specimen being examined.

Abstract: An intensified linear array instrument has been made by fiberoptically coupling a micro-channel plate proximity focused image intensifier tube to a Reticon RL512S linear photo-diode array. One of the principal advantages of intensification is that the sensitivity of the array can be increased to the photon-counting level. The pixel (p) readout rate is adjustable from 30 kp/s to 300 kp/s, so that rapid data acquisition is possible, and correction for nonuniformities in the instrument response can easily be made by using standard data processing equipment. The measured signal transfer, uniformity, spectral response, MTF and dark current characteristics of this instrument are presented, and alternate instrument designs are discussed. The electronic gating capability of an optional image tube assembly allows optical events as fast as several nanoseconds to be captured. This instrument has been designed in modules so that it can be coupled to a wide variety of existing spectroscopic optical systems. The modular design allows the optical interface flange, the image intensifier tube assembly, and the Reticon array assembly to be easily and quickly changed. It is possible to place the input face of the image intensifier directly in the focal plane of optical systems, such as spectrographs, so that no additional optical elements are required. This versatile instrument can provide more efficient data acquisition of spectroscopic or other linear array optical signals with less distortion than other instruments which do not use microchannel plate proximity focused image intensifiers.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: The device is comprised of an optical multiplexor directing sequentially and periodically a laser beam onto an array of discrete target points, wherein the laser beam is focused on a rotating mirror (12) by means of a converging lens (10). The beam reflected by the mirror (12) scans an array of adjacent converging lenses (14), of which the focal plane is situated also on the reflecting surface of the mirror (12). The beams are passed through a second system of converging lenses (18) located in another path of beams, these converging lenses (18) being each associated to one of the first converging lenses (14) and having their focal plane on the upper surface of the substrate (20) to be treated. If the target points are on a strip of paper, for example cigarette paper, endlessly and in motion, this strip is perforated at high speed with very fine holes.