Patents by Inventor Leonardus J. Grassens

Leonardus J. Grassens has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6532199
    Abstract: An apparatus for optical reading or recording information on an optical disc is rotatable about an axis of rotation. The apparatus includes a carriage, an objective lens, and an objective lens holder. The carriage has a center of mass. The carriage is movable relative to a frame along a path radial to the axis of rotation. The objective lens has an optical axis. The object lens is mounted to the objective holder so that the optical axis of the objective lens is within a first distance of intersecting the center of mass of the carriage. The holder is movable relative to the carriage so as to move the objective lens along its optical axis.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: March 11, 2003
    Assignee: Discovision Associates
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens
  • Patent number: 6266306
    Abstract: An analog to digital circuit assembly for use in an optical information includes a circuit for multiplexing a reference voltage input of an analog to digital converter to produce alternating normalized and referenced digital outputs of a plurality of analog signal inputs at a rate controlled by a sampling clock which includes a switch including first and second inputs, an output, and a control input for alternately connecting the first and the second inputs to the output, the output being applied to the reference voltage input.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: July 24, 2001
    Assignee: Discovision Associates
    Inventors: David L. Schell, Randolph Scott Crupper, Kurt W. Getreuer, Leonardus J. Grassens, David E. Lewis, Marvin B. Davis
  • Patent number: 6243336
    Abstract: An optical drive system includes an optical assembly, a light source, a lens positioned to direct light between the optical assembly and an information storage medium or disc, and an actuator suspending the lens. A photodetector is disposed in a path of returning light to measure light received from the medium. A monitoring circuit is provided to monitor a Quad Sum signal associated with return light. A first servomotor is employed to move the lens in a tracking direction and to move the lens during focus capture while system circuitry searches for a maximum Quad Sum signal. A second servomotor is employed to move the lens in a focusing direction. A first electronic circuit is provided to control the first and second servomotors.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: June 5, 2001
    Assignee: Discovision Associates
    Inventors: David L. Schell, Randolph S. Crupper, Marvin B. Davis, Kurt W. Getreuer, Leonardus J. Grassens, David E. Lewis
  • Patent number: 6141300
    Abstract: An apparatus for optically reading or recording information on an optical disc which is rotatable about an axis of rotation. The apparatus includes a frame, a carriage, a carriage drive, an objective lens, an objective lens holder, a focus drive, a fine tracking drive and an objective lens position sensor. The objective lens is mounted on the objective lens holder so that the optical axis of the objective lens substantially intersects the center of mass of the carriage. The fine motor, used for tracking and focus, has a center of mass that substantially lies on the optical axis and proximate the center of mass of the carriage.
    Type: Grant
    Filed: August 6, 1997
    Date of Patent: October 31, 2000
    Assignee: Discovision Associates
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens
  • Patent number: 6122232
    Abstract: A mechanical isolation apparatus suited for mitigating the effects of undesired mechanical forces upon disc drive system components, such as those found in compact disc, laser disc, magneto-optical player/recorder devices and similar devices. Component members are provided for mitigating the effects of compressive forces, vibration isolation, and thermal expansion, and may include compression ribs mounted on a housing for absorbing compressive forces. The housing is preferably adapted to fit on the end of a pole piece assembly. A crash stop may also be provided as a shock absorbing bumper and isolator to prevent a moving carriage from crashing into a solid surface. The compressive ribs and the crash stop are made of a material that exhibits minimum creep, such as a silicon rubber, polyurethane, or injection molded plastic.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: September 19, 2000
    Assignee: Discovision Associates
    Inventors: David L. Schell, Randolph S. Crupper, Marvin B. Davis, Kurt W. Getreuer, Leonardus J. Grassens, David E. Lewis
  • Patent number: 6058081
    Abstract: An optical drive system includes an objective lens subassembly for directing light from a light source toward an information storage medium. An amount of the directed lighted light is returned from the storage medium. An objective lens is disposed in the objective lens subassembly. A first servomotor moves, during focus capture, the objective lens to a first position, away from the first position toward the storage medium being read while looking for a maximum Quad Sum signal, and back away from the storage medium. An electronic control circuit is connected to the first servomotor. A servo error detector is coupled to the electronic control circuit and disposed in a path of light returning from the information storage medium.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: May 2, 2000
    Assignee: Discovision Associates
    Inventors: David L. Schell, Randolph Scott Crupper, Kurt W. Getreuer, Leonardus J. Grassens, David E. Lewis, Marvin B. Davis
  • Patent number: 6023379
    Abstract: An apparatus for aligning an actuator lens within a baseplate using a beam of radiant energy. The actuator lens has an actuator optical axis and an actuator optical center and the apparatus includes a frame, a cradle, a tower assembly, a lever assembly, and a gripper assembly. The cradle assembly is employed to hold the baseplate and is mounted to the frame with at least one degree of freedom of motion. The tower assembly defines a tower axis and is also mounted to the frame. The cradle and tower assemblies are positioned to receive the beam of radiant energy along the tower axis and analyze a spot profile of the beam. The lever assembly is rotatably mounted to the frame and the gripper assembly is mounted to the lever assembly.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: February 8, 2000
    Assignee: Discovision Associates
    Inventors: Leonardus J. Grassens, Hollis O'Neal Hall, II
  • Patent number: 5808980
    Abstract: An apparatus for optically reading or recording information on an optical disc which is rotatable about an axis of rotation. The apparatus includes a frame, a carriage movable relative to the frame along a path orthogonal to the axis of rotation, and a carriage drive for driving the carriage along the orthogonal path. Specific portions of the carriage drive are mounted on the carriage so that the carriage and the mounted portions define a center of carriage mass. An objective lens having an optical axis along a Z-axis and a center of lens mass is provided in an objective lens holder. The holder is movable relative to the carriage and receives a beam of light traveling along an X-axis. Flexures are provided for movably supporting the objective lens holder relative to the carriage. The flexures each have a hinge point within an XZ plane so that movement of the lens holder is provided by hinge action at the hinge points.
    Type: Grant
    Filed: April 11, 1995
    Date of Patent: September 15, 1998
    Assignee: Discovision Associates
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens
  • Patent number: 5790325
    Abstract: An apparatus for focusing an actuator lens within an optical disc carriage held by a baseplate assembly. The apparatus incudes a frame, a cradle assembly mounted to the frame, a tower assembly mounted to the frame, a lever assembly rotatably mounted to the frame, and a gripper assembly mounted to the lever assembly. The cradle assembly includes a baseplate alignment assembly having a source of radiant energy for projecting a beam of radiant energy, a member for determining the tilt alignment of the beam with respect to the tower assembly, and tilt actuators for aligning the tilt of the beam with respect to the tower assembly. The tower assembly includes a video camera having a camera lens, a tower magnifying lens, and a monitor for displaying a representation of a beam of radiant energy passing through the tower magnifying lens and into the video camera.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: August 4, 1998
    Assignee: Discovision Associates
    Inventors: Leonardus J. Grassens, Hollis O'Neal Hall, II
  • Patent number: 5768035
    Abstract: An apparatus is described for mounting an actuator lens within an optical disc carriage held by a baseplate assembly. The apparatus includes a frame, a cradle assembly mounted to the frame with at least one degree of freedom of motion, a tower assembly mounted to the frame, a lever assembly rotatably mounted to the frame, and a gripper assembly mounted to the lever assembly. The cradle assembly includes a baseplate alignment assembly having a source of radiant energy for projecting a beam of radiant energy, means for determining the tilt alignment of the beam with respect to the tower assembly, and a plurality of tilt actuators for aligning the tilt of the beam with respect to the tower assembly. The tower assembly includes a video camera having a camera lens, a tower magnifying lens, and a monitor for displaying a presentation of a beam of radiant energy passing through the tower magnifying lens and into the video camera.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 16, 1998
    Inventors: Leonardus J. Grassens, Hollis O'Neal Hall, II
  • Patent number: 5729511
    Abstract: An optical drive system includes an optical assembly, a light source capable of transmitting light through the optical assembly, an objective lens positioned to direct light between the optical assembly and a respective information storage medium, and an actuator suspending the objective lens for relative motion thereof with respect to the actuator. A photodetector is disposed in a path of returning light to measure return light received from the respective medium. A monitoring circuit is provided to monitor a Quad Sum signal associated with the return light. A first servomotor is employed to move the objective lens in a tracking direction relative to the actuator and to move the objective lens during focus capture relative to the respective medium being read while system circuitry searches for a maximum Quad Sum signal. A second servo motor is employed to move the objective lens in a focusing direction relative to the actuator assembly.
    Type: Grant
    Filed: January 25, 1995
    Date of Patent: March 17, 1998
    Assignee: Discovision Associates
    Inventors: David L. Schell, Randolph S. Crupper, Marvin B. Davis, Kurt W. Getreuer, Leonardus J. Grassens, David E. Lewis
  • Patent number: 5708633
    Abstract: A method and apparatus for manufacturing information storage devices is described herein. Two embodiments of the invention are disclosed. In particular, the invention includes, but is not limited to, a bearing insertion device, a lens insertion device, a coarse coil gluing tool, a spring gluing tool, a device for gluing pole pieces, a pentaprism insertion and inspection tool, a constants and transfers test, an optics module alignment device, wedge, microprism and beamsplitter insertion devices, a read channel alignment test, a mass balance attachment invention, a position sensor alignment tool, an invention for the attachment of focus and radial coils, a quality control test for test an optical storage device prior to insertion of the objective lens, and a servo system test. The invention described herein is designed to manufacture information storage devices with increased quality and efficiency.
    Type: Grant
    Filed: February 6, 1996
    Date of Patent: January 13, 1998
    Assignee: Discovision Associates
    Inventors: Zdenek A. Hollen, Russell A. Meyer, Kent Murphy, Robert G. Russell, Christopher J. Monsen, Herbert E. Heaton, Christopher A. Knorr, David L. Papiernik, James K. Louie, Leonardus J. Grassens, Wilhelm Taylor, Charles DePuy, Douglas E. Hoover, Gary Anderson, Hollis O'Neal Hall, II
  • Patent number: 5532989
    Abstract: An apparatus for optically reading or recording information on an optical disc which is rotatable about an axis of rotation. The apparatus includes a frame, a carriage, a carriage drive, an objective lens, an objective lens holder, a focus drive and a fine tracking drive. The objective lens is mounted on the objective lens holder so that the optical axis of the objective lens substantially intersects the center of mass of the carriage. The fine motor, used for tracking and focus, has a center of mass that substantially lies on the optical axis and proximate the center of mass of the carriage.
    Type: Grant
    Filed: March 6, 1995
    Date of Patent: July 2, 1996
    Assignee: Discovision Associates
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens
  • Patent number: 5313332
    Abstract: A device for reading information from or writing information to an optical disc memory system using light from a laser diode includes an upper and lower flexure suspension. Both flexure suspensions are mounted on both an objective lens holder and its base. Each of these flexures is U-shaped and the central part of each leg of the U is a stiff beam. At each end of the control beam is provided a tracking hinge. Outward from the tracking hinges are a pair of focusing hinges which are separated from the tracking hinges by means of spacing beam sections. The unique configuration of the system allows these parallel mounted flexures to move in only two rigid modes namely, displacement along the x-axis (tracking) and displacement along the z-axis (focusing). These two rigid modes allow the objective lens to be re-positioned so that light beams may strike the information medium correctly.
    Type: Grant
    Filed: July 26, 1993
    Date of Patent: May 17, 1994
    Assignee: Applied Magnetics Corporation
    Inventors: David L. Schell, Leonardus J. Grassens, Kurt W. Getreuer
  • Patent number: 5265079
    Abstract: The present invention is an apparatus for optical reading or recording information on an optical information medium, wherein as a result of the relative position of the components of the apparatus and the magnitude and application points of the forces exerted to track and focus, the objective lens through which information is read from the information medium, prevents the objective lens from being affected by most resonances, motor forces and reaction forces. This is critical in that in optical recording, displacements of 0.02 micrometers can easily be picked up. Specifically, one aspect of the invention is an apparatus for optically reading or recording information on an optical disk which is rotatable about an axis of rotation, wherein the apparatus includes a frame, a carriage, a carriage drive, an objective lens, an objective lens holder and a focus drive. The carriage drive (i.e.
    Type: Grant
    Filed: February 15, 1991
    Date of Patent: November 23, 1993
    Assignee: Applied Magnetics Corporation
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens
  • Patent number: 5177640
    Abstract: A two-axis electromagnetic actuator for positioning an objective lens in an optical recording system is disclosed wherein the objective lens is mounted on a lens holder. The lens holder is positioned within a magnetic field created by two pairs of permanent magnets. A tracking coil is wound around the lens holder and two focus coils are affixed to the tracking coil adjacent the permanent magnet pairs. The lens holder suspended between the magnet pairs by flexures supported on a circuit board. The circuit board further includes electrical contacts for supplying current to the focus and tracking coils in accordance with feedback signals generated by a servo system. The current through the coils interacts with the magnetic field produced by the magnets to move the lens holder and objective lens carried thereon and effect tracking and focusing of a laser beam exiting the lens upon the surface of an optical disc.
    Type: Grant
    Filed: October 8, 1991
    Date of Patent: January 5, 1993
    Assignee: Applied Magnetics Corporation
    Inventor: Leonardus J. Grassens
  • Patent number: 5136558
    Abstract: An optical disc player/recorder incorporates a laser, and an electromagnetically driven objective lens. The objective lens is mounted to a lensholder which is movable with respect to a base. A single pair of permanent magnets are mounted to the lensholder, and two pair of electromagnetic coils are mounted to the base. The coils and magnets are positioned such that one set of coils is collinear with the direction of magnetization of the permanent magnets and the other set of coils is perpendicular to the direction of magnetization of the magnets. Electromagnetic fields generated by the coils are used to move the objective lens in either a focus direction or a tracking direction. The magnets are mounted on the moveable objective lensholder, while the coils are attached in a heat-sink relationship to the fitted base. The objective lens rests on top of the objective lensholder which is suspended with respect to the base by a pair of flexures.
    Type: Grant
    Filed: June 20, 1989
    Date of Patent: August 4, 1992
    Assignee: Applied Magnetics Corporation
    Inventors: Kurt W. Getreuer, Leonardus J. Grassens, David L. Schell
  • Patent number: 4945526
    Abstract: An actuator assembly for use in an optical disk information processing system is disclosed having improved performance characteristics for achieving a large radial movement frequency bandwidth. The actuator assembly includes an actuator body defining a rail channel for movement on a single rail. The device is configured so that the center of mass of the actuator body is above the friction surfaces between the rail and the rail channel. The actuator body includes an optical channel for receiving an optical beam to be focused on an optical disk. This optical channel is positioned between two focus supports which support a lens holder which is movable for focusing the incoming optical beam onto the optical disk. The focusing motor, including a coil and focusing magnets, is positioned below the center of mass of the actuator to achieve a balanced device. The radial drive assembly for the device includes a coil directly wound on the actuator body which encircles the optical channel and the rail channel.
    Type: Grant
    Filed: October 18, 1988
    Date of Patent: July 31, 1990
    Assignee: Laser Magnetic Storage International Company
    Inventors: Gerardus L. M. Jansen, Leonardus J. Grassens, Zdenek T. Hollen
  • Patent number: 4885998
    Abstract: A patient support system for irradiation therapy or treatment simulation comprises a main arm 1 on a sub-floor mounted pivot 10 about a first vertical axis 17, which supports a further arm 49 rotatable about a second vertical axis 16. At the other end of the arm 49 a vertical pillar 4, pivotable about a third vertical axis 15, supports a vertically displaceable carriage 3 on which a patient support table top 2 is directly mounted. A control system is described which enables x, y coordinate command values to control respective drives associated with the three vertical axes to position a patient quickly and accurately relative to the treatment isocenter. The system requires only a shallow well while providing a large range of vertical lift. Furthermore, no sub-table x-y carriage is required increasing patient accessability.
    Type: Grant
    Filed: March 15, 1988
    Date of Patent: December 12, 1989
    Assignee: U.S. Philips Corporation
    Inventors: Francis J. Span, Leopold H. Hissel, Leonardus J. Grassens
  • Patent number: 4683520
    Abstract: A shock mount for mounting an electrical apparatus to a chassis includes a resilient buffer mounted to the apparatus and to the end of an L-shaped arm. The L-shaped arm is joined to and integral with the chassis and is arranged to support bending and torsional loads to absorb mechanical shock.
    Type: Grant
    Filed: July 14, 1986
    Date of Patent: July 28, 1987
    Assignee: Laser Magnetic Storage International Company
    Inventors: Leonardus J. Grassens, Peter J. Janssen