Patents Represented by Attorney L. Zalman
  • Patent number: 4080652
    Abstract: A memory control processor adapted to expand a random access or accelerator memory by logical overlays which performs these overlays into memory fields (pages) on the basis of page usage history. To provide a quick reference to page use a chronological sequence is established by links rather than by reordering a stack. This link sequence is tied by very limited leads to the rest of the memory control processor and can therefore be updated during each memory access. In addition the memory control processor includes a task priority logic integrating various competing memory access requests with the overlay operations. To achieve the various transfer modes in the quickest time the memory control processor is organized around a wide control memory storing the tank servicing sequences. The width of the control memory and the associated task logic allow general purpose microprogrammable direct memory access which may further be utilized in multiplexed fashion to accommodate various concurrent tasks.
    Type: Grant
    Filed: February 17, 1977
    Date of Patent: March 21, 1978
    Assignee: Xerox Corporation
    Inventors: David Cronshaw, William D. Turner, Jack E. Shemer
  • Patent number: 4080651
    Abstract: A memory control processor adapted to expand a random access or accelerator memory by logical overlays which performs these overlays into memory fields (pages) on the basis of page usage history. To provide a quick reference to page use a chronological sequence is established by links rather than by reordering a stack. This link sequence is tied by very limited leads to the rest of the memory control processor and can therefore be updated during each memory access. In addition the memory control processor includes a task priority logic integrating various competing memory access requests with the overlay operations. To achieve the various transfer modes in the quickest time the memory control processor is organized around a wide control memory storing the task servicing sequences. The width of the control memory and the associated task logic allow general purpose microprogrammable direct memory access which may further be utilized in multiplexed fashion to accommodate various concurrent tasks.
    Type: Grant
    Filed: February 17, 1977
    Date of Patent: March 21, 1978
    Assignee: Xerox Corporation
    Inventors: David Cronshaw, William D. Turner, Jack E. Shemer
  • Patent number: 4080633
    Abstract: An optical flying spot scanner having a lens array positioned between a scan line and a detector array and inclined at an angle to the axis of the scan line. Each of the lenses of the lens array has a coordinate position in a plane parallel to the scan line related to a particular segment of the scan line such that the information content of each segment of the scan line is transmitted to a different one of the tiered detectors of the detector array.
    Type: Grant
    Filed: July 15, 1976
    Date of Patent: March 21, 1978
    Assignee: Xerox Corporation
    Inventor: Gary K. Starkweather
  • Patent number: 4077019
    Abstract: A heterojunction diode laser which achieves transverse mode control by providing adjacent to the active region layer of the laser a layer having a thickness substantially less than the thickness of the active region layer and of a material having a bandgap higher than the bandgap of the material of the active region layer. All transverse modes have increased penetration into a lossy substrate via the thin layer with the loss being least for the lowest order mode such that only the lowest order mode can be made to lase at low pumping current levels.
    Type: Grant
    Filed: January 5, 1976
    Date of Patent: February 28, 1978
    Assignee: Xerox Corporation
    Inventors: William Streifer, Donald R. Scifres, Robert D. Burnham
  • Patent number: 4063189
    Abstract: A heterojunction diode laser which utilizes leaky wave coupling through a thin confining layer or a pair of thin confining layers to produce a high powered, highly collimated output beam with high external differential quantum efficiency, and relative freedom from facet damage resulting from high optical density.
    Type: Grant
    Filed: April 8, 1976
    Date of Patent: December 13, 1977
    Assignee: Xerox Corporation
    Inventors: Donald R. Scifres, Robert D. Burnham, William Streifer
  • Patent number: 4052715
    Abstract: Method and apparatus for expanding the number of grey scale values in a digital flying-spot scanning system. The scanned recording medium is divided into a plurality of unit cells, each of which is assigned a desired grey scale value, and each unit cell is further divided into a plurality of subcells formed by a plurality of adjacent portions of scan lines comprising digitally controlled segments. The grey scale value of the unit cell is dependent upon the portion of the subcells within the unit cell which are activated or deactivated by the scanning beam. Additionally, the number of grey scale values between particular numbers of activated subcells is expanded by providing varying patterns of predetermined numbers of subcells within the unit cell with the varying patterns producing the optical effect of varying grey scale levels.
    Type: Grant
    Filed: February 25, 1976
    Date of Patent: October 4, 1977
    Assignee: Xerox Corporation
    Inventor: William Streifer
  • Patent number: 4045749
    Abstract: An electrically pumped distributed feedback grating coupled diode laser having an optical cavity containing two closely spaced layers, a first of the layers is electrically pumped and the second of the layers is corrugated. Optical wavelength radiation and amplification of said radiation is generated in the first layer by carrier recombination with the radiation spreading to the second layer for coherent reflection by the corrugation and for low loss transmission. Carrier confinement in the first layer and optical confinement in the optical cavity are achieved by surrounding each of these layers by materials having a higher bandgap and lower index of refraction than the materials of the first and the second layers. The corrugation of the second layer can extend over only a portion of the length of the second layer such that the uncorrugated portion of the second layer provides a low loss waveguide.
    Type: Grant
    Filed: November 24, 1975
    Date of Patent: August 30, 1977
    Assignee: Xerox Corporation
    Inventors: Robert D. Burnham, Donald R. Scifres, William Streifer
  • Patent number: 4042939
    Abstract: Recording machine such as electrostatic printer/plotter or facsimile plotter includes housing construction and associated operating components whereby overall external width reduction is accomplished without loss of function using liftable lid and method of cross-bracing. Machine serviceable through removable bottom closure panel supporting an electronic chassis. Operating stations, such as recording assembly including both electrostatic latent image recording station and a toner developing station, and web-cutting assembly each includes portions in both lid and base of housing to be yieldingly held together in cooperating relation by hinged latching panel in which the hinge pin supplies spring action to urge and retain the latching panel in its detented position.
    Type: Grant
    Filed: September 12, 1975
    Date of Patent: August 16, 1977
    Assignee: Xerox Corporation
    Inventors: William A. Lloyd, Salvatore Barone, Gerald E. Hooper, Keith E. McFarland
  • Patent number: 4037225
    Abstract: A keyboard encoding system which utilizes electronic hysteresis to prevent undesired key stroke encoding. The output of a capacitive switch matrix is supplied to a sense amplifier which has its sensitivity increased if a particular switch of the switch matrix was closed the last scan cycle. The status of the switches of the switch matrix during the last scan cycle is provided by a shift register having a number of stages equal to the number of switches of the matrix. The sense amplifier includes a comparator which receives an input indicative of the state of a particular matrix switch during the present scan cycle and an input from the shift register indicative of the status of the particular matrix switch the previous scan cycle. If the input from the shift register is high, the sensitivity of the sense amplifier is increased.
    Type: Grant
    Filed: November 25, 1975
    Date of Patent: July 19, 1977
    Assignee: Xerox Corporation
    Inventor: Wilbur E. DuVall
  • Patent number: 4035061
    Abstract: An optical display comprised of an array of small focusable image elements in conjuction with a corresponding array of optical stops or filters, one optical stop or filter being aligned with each image element. Upon the application of a force field to selected ones of the image elements, the optical focal point of those image elements is changed to thereby allow ambient light incident upon those image elements to be focused differently than it was prior to the application of the electric field whereby the optical stops aligned with the selected image elements intercept a different portion of the ambient light reflected or transmitted the selected image elements than do the optical stops aligned with non-selected image elements to thereby provide a display having light and dark areas.
    Type: Grant
    Filed: March 26, 1976
    Date of Patent: July 12, 1977
    Assignee: Xerox Corporation
    Inventor: Nicholas K. Sheridon
  • Patent number: 4035068
    Abstract: An optical system for minimizing the speckle observed in a projected image, the image being produced by a projection display device. Coherent or non-coherent light illuminates the projection display device image and an image thereof is formed at an intermediate image plane. A narrow angle diffuser is positioned at the intermediate image plane and produces an enlarged illuminating aperture at the Fourier transform plane. The relatively large angle subtended by the illuminating aperture at a second image plane reduces the spatial coherence of the image formed thereat.
    Type: Grant
    Filed: June 25, 1975
    Date of Patent: July 12, 1977
    Assignee: Xerox Corporation
    Inventor: Eric G. Rawson
  • Patent number: 4034408
    Abstract: A flying spot scanning system is provided by utilizing reflected light from a multifaceted rotating polygon which is then directed to the scanned medium. A light source illuminates at least two contiguous facets of the polygon during each scanning cycle, to provide the desired sequence of spot scanning. To assure a uniform spot size at the scanned medium, an optical convolution of elements is selected in combination with the light source such that an adequate depth of focus at the medium is assured. In each scanning cycle, information is transmitted to the scanned medium by modulating the light from the light source in accordance with a video signal.
    Type: Grant
    Filed: July 7, 1975
    Date of Patent: July 5, 1977
    Assignee: Xerox Corporation
    Inventor: Gary K. Starkweather
  • Patent number: 4033796
    Abstract: A method of making a buried-heterostructure (BH) diode injection laser capable of operating at low room temperature thresholds and in the lowest order TE, TM, or TEM modes. Following formation of a pump current confining layer in a substrate, an elongated groove or channel is formed in the substrate with the groove extending through the pump current confining layer. A first light guiding and carrier confining layer, an active layer, and a second light guiding and carrier confining layer are then grown successively on the grooved surface of the substrate with the active layer material having both a higher index of refraction and lower bandgap than the material(s) of the light guiding and carrier confining layers.
    Type: Grant
    Filed: June 23, 1975
    Date of Patent: July 5, 1977
    Assignee: Xerox Corporation
    Inventors: Robert D. Burnham, Donald R. Scifres
  • Patent number: 4034343
    Abstract: An optical character recognition system for identifying typewritten characters and converting such to standard code for transmission. To achieve recognition of a character, the character, as it is scanned, is recorded in a corresponding array in memory and the memory address for each scan coordinate is then modified to correspond with the virtual character center. This coordinate center of the character is derived by inspection of the scanning array in parallel with the memory storing pass to determine the two adjacent all white rows and columns bounding the character. The coordinate center is then calculated by dividing the bounded row and column increment by two. The recognition of the character pattern is then performed by a set of Boolean discriminants selected to achieve the highest probability of in - character hits against a lowest probability of misses.
    Type: Grant
    Filed: October 1, 1976
    Date of Patent: July 5, 1977
    Assignee: Xerox Corporation
    Inventor: Michael E. Wilmer
  • Patent number: 4027961
    Abstract: An apparatus which can function either in a copier mode or in a raster scan mode. A first unit of the apparatus, containing elements to produce an information modulated, scanning light beam, is movably mounted upon a second unit of the apparatus, containing optical elements for directing light upon a photosensitive medium, such that the movable unit can be located clear of the document supporting platen of the second unit to provide copier operation or can be located immediately adjacent the platen of the second unit to provide raster scanning operation. Optical means are provided in the movable unit to provide light focusing capabilities for the raster scan mode of operation.
    Type: Grant
    Filed: April 6, 1976
    Date of Patent: June 7, 1977
    Assignee: Xerox Corporation
    Inventor: Gary K. Starkweather
  • Patent number: 4023993
    Abstract: An electrically pumped, solid-state laser device having a grating or physical periodic structure in a region, or adjacent a region, of semiconductor material that functions as a light wave guide. The spacing of the perturbations of the periodic structure are selected to be an integer number of half wavelengths of the desired laser wavelength. The electrically pumped, solid-state laser device can be a single heterojunction device or a double heterojunction device. Both devices are formed by a process which provides for formation of the periodic structure prior to formation of the light guiding layer or region. Due to this process a periodic structure having a desired spacing and substantial depth is produced, which structure produces Bragg Scattering which couples and reinforces light traveling through the light guiding layer in both directions in a coherent manner such that reflections are in phase, thus allowing laser operation in the absence of discrete end reflectors.This is a division of application Ser.
    Type: Grant
    Filed: August 28, 1975
    Date of Patent: May 17, 1977
    Assignee: Xerox Corporation
    Inventors: Donald R. Scifres, William Streifer, Robert D. Burnham
  • Patent number: 4014030
    Abstract: Half-tone imaging is achieved in a flying spot scanning system wherein a highly collimated light beam is modulated with imaging information, reflected from a multifaceted rotating polygon and directed to a scanned medium through a light attenuating member. The latter member is supported proximate the imaging focal plane and orthogonal to the collimated, reflected light beam. The light attenuating member has an optical light transmission characteristic that varies in a continuous and cyclic pattern with a cycle period at least about ten times the maximum lateral extent of the collimated light beam, thereby serving to alter the system imaging from contrasting black and white patterns to half tones and gray colorations.
    Type: Grant
    Filed: February 23, 1976
    Date of Patent: March 22, 1977
    Assignee: Xerox Corporation
    Inventors: Howard M. Stark, William Streifer
  • Patent number: 4012776
    Abstract: A laser scanning system for scanning an original color document with light of three different colors. In a first operative sequence, the output beam from a laser, which comprises light of a first color, is incident upon a rotating scanning member, the light therefrom being directed to a reflecting first portion of a luminescent screen, the light reflected from said first screen portion completely scanning the entire original document. In a second operative sequence, the laser light from said rotating scanning member is directed to a second portion of said luminescent screen having a material associated therewith which produces light of a second color in response to the incident laser light, the light produced by said second portion of said luminescent screen scanning the entire original document.
    Type: Grant
    Filed: February 2, 1976
    Date of Patent: March 15, 1977
    Assignee: Xerox Corporation
    Inventor: Peter Mrdjen
  • Patent number: 4006432
    Abstract: A heterojunction diode laser which produces a highly collimated, polarized light beam perpendicular to the plane of the PN junction of the laser rather than through cleaved end faces in the plane of the PN junction. The diode laser includes a periodic structure which is buried at a heterojunction interface and in contact with a light waveguide layer. The periodic structure acts to produce the feedback necessary for lasing. If the spacing of the teeth of the periodic structure are an integer number of wavelengths of the light photons produced in the laser, the light beam exits at an angle perpendicular to the plane of the PN junction. If a tooth spacing is chosen that is not equal to an integer number of wavelengths of the light photons produced in the laser, the light beam may emerge from the diode at an angle other than the normal with the specific angle determined by the particular tooth spacing.
    Type: Grant
    Filed: October 15, 1974
    Date of Patent: February 1, 1977
    Assignee: Xerox Corporation
    Inventors: William Streifer, Donald R. Scifres, Robert D. Burnham
  • Patent number: 4001892
    Abstract: An apparatus for removing contaminant particles from an enclosure containing a rotating magnetic disk by using the air flow created by rotation of the disk. A tacky substance is provided at a point of maximum centrifugal force within the enclosure so that contaminant particles are permanently captured. Means can be provided for refreshing the tacky substance.
    Type: Grant
    Filed: March 17, 1975
    Date of Patent: January 4, 1977
    Assignee: Xerox Corporation
    Inventors: Vittorio Castelli, Stephen T. Chai