Patents by Inventor Stephen W. Marshall

Stephen W. Marshall 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: 8723846
    Abstract: According to one embodiment, a method of increasing a perceived resolution of a display includes directing light at a optical dithering element and repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the mirror alternately reflects light to a first position on the display and then to a second position on the display. Each transition of the mirror includes controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined drive signal to the optical dithering element to smoothly accelerate and decelerate the element during the traverse between the first and second positions.
    Type: Grant
    Filed: August 22, 2011
    Date of Patent: May 13, 2014
    Assignee: Texas Instruments Incorporated
    Inventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
  • Patent number: 8444271
    Abstract: The disclosure provides an apparatus for reducing speckle in a projection visual display (PVD) system, a method of reducing visible speckle in a PVD system and a PVD system incorporating the method or apparatus. In one embodiment, the apparatus includes a diffuser interposable in an optical path of a PVD system and a diffuser actuator having a single drive axis configured to cause the diffuser to travel in a Lissajous curve at least partially transverse to the optical path.
    Type: Grant
    Filed: October 3, 2011
    Date of Patent: May 21, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: James C. Dunphy, Stephen W. Marshall
  • Patent number: 8237779
    Abstract: Video signals in a video stream are encoded by inserting reference signals in the video stream such that the encoded video stream carry both reference signals and video signals being coded. In the decoding stage, reference images generated from the reference signals are detected and used for identifying the encoded video signals based upon the profiles of the detected reference images. An imaging architecture capable of using the coding scheme comprises a shutter that can be implemented as a dual-processor configuration.
    Type: Grant
    Filed: April 4, 2008
    Date of Patent: August 7, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Stephen W. Marshall, Michael David McCormick, Henry William Neal, Stanford Porter Hudson
  • Patent number: 8113662
    Abstract: In accordance with the teachings of the present disclosure, a system and method for displaying an image are provided. In one embodiment, the method includes receiving a laser through a rotary diffuser. The rotational speed of the rotary diffuser may be continuously varied to reduce the effect of an image artifact in a light pattern. The image artifact may be caused by an imperfection in the rotary diffuser. The light pattern is projected on a display device.
    Type: Grant
    Filed: January 22, 2009
    Date of Patent: February 14, 2012
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Publication number: 20120019918
    Abstract: The disclosure provides an apparatus for reducing speckle in a projection visual display (PVD) system, a method of reducing visible speckle in a PVD system and a PVD system incorporating the method or apparatus. In one embodiment, the apparatus includes a diffuser interposable in an optical path of a PVD system and a diffuser actuator having a single drive axis configured to cause the diffuser to travel in a Lissajous curve at least partially transverse to the optical path.
    Type: Application
    Filed: October 3, 2011
    Publication date: January 26, 2012
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: James C. Dunphy, Stephen W. Marshall
  • Publication number: 20110304596
    Abstract: According to one embodiment, a method of increasing a perceived resolution of a display includes directing light at a optical dithering element and repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the mirror alternately reflects light to a first position on the display and then to a second position on the display. Each transition of the mirror includes controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined drive signal to the optical dithering element to smoothly accelerate and decelerate the element during the traverse between the first and second positions.
    Type: Application
    Filed: August 22, 2011
    Publication date: December 15, 2011
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
  • Patent number: 8031403
    Abstract: The invention provides an apparatus for reducing speckle in a projection visual display (PVD) system, a method of reducing visible speckle in a PVD system and a PVD system incorporating the method or apparatus. In one embodiment, the apparatus includes a diffuser interposable in an optical path of a PVD system and a diffuser actuator having a single drive axis configured to cause the diffuser to travel in a lissajous curve at least partially transverse to the optical path.
    Type: Grant
    Filed: November 30, 2007
    Date of Patent: October 4, 2011
    Assignee: Texas Instruments Incorporated
    Inventors: James C. Dunphy, Stephen W. Marshall
  • Patent number: 7710350
    Abstract: According to one embodiment, a method for providing position feedback for a device includes providing a photointerrupter having a light-emitting diode, a phototransistor, and an aperture between the light-emitting diode and the phototransistor. For a given size aperture, a current through the phototransistor is a function of a current through the light-emitting diode. The method also includes controlling the current through the light-emitting diode current such that a change in the effective aperture size results in a desired approximately proportional change in current through the phototransistor. While controlling the current through the light-emitting diode, a portion of the aperture is blocked by an arm that has a position indicative of the position of the device. The method also includes providing a signal indicative of the change in current through the photodiode as an indication of the change in position of the device.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: May 4, 2010
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Publication number: 20090251531
    Abstract: Video signals in a video stream are encoded by inserting reference signals in the video stream such that the encoded video stream carry both reference signals and video signals being coded. In the decoding stage, reference images generated from the reference signals are detected and used for identifying the encoded video signals based upon the profiles of the detected reference images. An imaging architecture capable of using the coding scheme comprises a shutter that can be implemented as a dual-processor configuration.
    Type: Application
    Filed: April 4, 2008
    Publication date: October 8, 2009
    Applicant: Texas Instruments Incorporated
    Inventors: Stephen W. Marshall, Michael David Mc Cormick, Henry William Neal, Stanford Porter Hudson
  • Publication number: 20090009871
    Abstract: The invention provides an apparatus for reducing speckle in a projection visual display (PVD) system, a method of reducing visible speckle in a PVD system and a PVD system incorporating the method or apparatus. In one embodiment, the apparatus includes a diffuser interposable in an optical path of a PVD system and a diffuser actuator having a single drive axis configured to cause the diffuser to travel in a lissajous curve at least partially transverse to the optical path.
    Type: Application
    Filed: November 30, 2007
    Publication date: January 8, 2009
    Applicant: Texas Instruments Incorporated
    Inventors: James C. Dunphy, Stephen W. Marshall
  • Publication number: 20080158263
    Abstract: In accordance with the teachings of the present disclosure, a system and method for increasing the bit-depth of a video display system using plural spatial light modulators are provided. In one embodiment, the method includes illuminating one or more first spatial light modulators. The method also includes receiving a signal indicating the illumination provided to at least a portion of at least one of the one or more first spatial light modulators should be modified. The method further includes intensity-modulating, by one or more second spatial light modulators in response to the signal, the illumination provided to at least a portion of the at least one of the one or more first spatial light modulators.
    Type: Application
    Filed: December 28, 2006
    Publication date: July 3, 2008
    Applicant: Texas Instruments Incorporated
    Inventors: Sue Hui, Stephen W. Marshall
  • Publication number: 20080151104
    Abstract: According to one embodiment, a method of increasing a perceived resolution of a display includes directing light at a optical dithering element and repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the mirror alternately reflects light to a first position on the display and then to a second position on the display. Each transition of the mirror includes controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined drive signal to the optical dithering element to smoothly accelerate and decelerate the element during the traverse between the first and second positions.
    Type: Application
    Filed: February 25, 2008
    Publication date: June 26, 2008
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
  • Patent number: 7336290
    Abstract: According to one embodiment, a method of increasing a perceived resolution of a display includes directing light at a optical dithering element and repeatedly transitioning the optical dithering element from a first position to a second position and then back to the first position such that the mirror alternately reflects light to a first position on the display and then to a second position on the display. Each transition of the mirror includes controlling any overshoot or ringing in the position of the optical dithering element by providing a predetermined drive signal to the optical dithering element to smoothly accelerate and decelerate the element during the traverse between the first and second positions.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: February 26, 2008
    Assignee: Texas Instruments Incorporated
    Inventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
  • Patent number: 7330298
    Abstract: An optical system for projecting an image having x and y axes onto a image plane is provided. The system includes an SLM device spaced from the image plane, the SLM device having a plurality of pixels operable to project pixels of the image onto the image plane and positioned such that the individual pixels of the projected image are oriented at substantially 45 degrees relative to the x and y axes of the image. The system further includes an optic element disposed between the SLM device and the image plane and a linear displacement device operatively connected to and operable to selectively displace at least one of the SLM device and the optic element. A method for projecting an image onto a image plane is also provided.
    Type: Grant
    Filed: February 4, 2005
    Date of Patent: February 12, 2008
    Assignee: Texas Instruments Incorporated
    Inventors: William M. Bommersbach, Donald C. Whitney, Frederick C. Wedemeier, Roger S. Carver, Steven M. Penn, Stephen W. Marshall, Frank J. Poradish, Donald A. Powell
  • Patent number: 7321458
    Abstract: According to one embodiment, a method for controlling positioning of an optical dithering element includes repeatedly driving the optical dithering element approximately between a plurality of desired positions by a generally periodic drive waveform. During a particular period of the drive waveform, the actual position of the optical dithering element is determined at a plurality of sample times. For each of the determined actual positions of the optical dithering element, a position error indicator is determined based upon whether the magnitude of the actual position is greater than, less than, or the same as a desired setpoint for the position of the optical dithering element. The method also includes generating an error signature for the particular period based on the determined error indicators and modifying the drive waveform in response to the error signature.
    Type: Grant
    Filed: October 30, 2006
    Date of Patent: January 22, 2008
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Patent number: 7173601
    Abstract: According to one embodiment, a method for providing position feedback for a device includes providing a photointerrupter having a light-emitting diode, a phototransistor, and an aperture between the light-emitting diode and the phototransistor. For a given size aperture, a current through the phototransistor is a function of a current through the light-emitting diode. The method also includes controlling the current through the light-emitting diode current such that a change in the effective aperture size results in a desired approximately proportional change in current through the phototransistor. While controlling the current through the light-emitting diode, a portion of the aperture is blocked by an arm that has a position indicative of the position of the device. The method also includes providing a signal indicative of the change in current through the photodiode as an indication of the change in position of the device.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: February 6, 2007
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Patent number: 7139040
    Abstract: A system and method for correcting non-periodic event time of arrival data in a control system. The system and methods are particularly applicable to the speed and phase control of a color wheel used with spatial light modulators. The circuitry automatically and accurately compensates for non-periodic index signals occurring when one or more index marks on the color wheel are misplaced. The system adds to or subtracts clock pulses from the actual time of arrival of a specific index mark until the corrected value equals the desired or nominal value. The system then generates a PWM signal for controlling the speed and phase of the color wheel.
    Type: Grant
    Filed: December 29, 2003
    Date of Patent: November 21, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Patent number: 7130105
    Abstract: According to one embodiment, a method for controlling positioning of an optical dithering element includes repeatedly driving the optical dithering element approximately between a plurality of desired positions by a generally periodic drive waveform. During a particular period of the drive waveform, the actual position of the optical dithering element is determined at a plurality of sample times. For each of the determined actual positions of the optical dithering element, a position error indicator is determined based upon whether the magnitude of the actual position is greater than, less than, or the same as a desired setpoint for the position of the optical dithering element. The method also includes generating an error signature for the particular period based on the determined error indicators and modifying the drive waveform in response to the error signature.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: October 31, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Patent number: 7079095
    Abstract: A micromirror capable of analog pulse width modulation, and method thereof. A capacitor (406) in each micromirror element stores a charge representative of one pixel of image data. A comparator (414) compares the image data signal stored on the capacitor (406) to a reference signal from a reference signal generator (416). Depending on the results of the comparison, the address electrodes (418) of the micromirror are biased to deflect the micromirror (412). As either the image data charge stored on the capacitor (406), or the reference voltage changes, the output of the comparator (414) changes to alter the position of the micromirror (412).
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: July 18, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall
  • Patent number: 6738104
    Abstract: A new method for phase locking the color wheel in a color field-sequential projection display. At periodic interrupts, the method determines which color wheel index mark should be driven into coincidence with the Vsync signal. It does this by measuring the delay between Vsync and any index mark and then based on the current state of the spoke-sync counter and this delay value, a new next state is determined to drive the nearest index mark to Vsync to the Vsync position. At worst case this technique requires only one-half a color wheel revolution of phase correction to re-lock the system when the TV channel is changed and for the 5/2 and 7/2 spoke-sync modes, popular 50 Hz and 60 Hz modes, only one-quarter revolution of phase correction of the color wheel is required for re-lock.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: May 18, 2004
    Assignee: Texas Instruments Incorporated
    Inventor: Stephen W. Marshall