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).
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Patent number: 8723846Abstract: 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: GrantFiled: August 22, 2011Date of Patent: May 13, 2014Assignee: Texas Instruments IncorporatedInventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
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Patent number: 8444271Abstract: 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: GrantFiled: October 3, 2011Date of Patent: May 21, 2013Assignee: Texas Instruments IncorporatedInventors: James C. Dunphy, Stephen W. Marshall
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Patent number: 8237779Abstract: 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: GrantFiled: April 4, 2008Date of Patent: August 7, 2012Assignee: Texas Instruments IncorporatedInventors: Stephen W. Marshall, Michael David McCormick, Henry William Neal, Stanford Porter Hudson
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Patent number: 8113662Abstract: 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: GrantFiled: January 22, 2009Date of Patent: February 14, 2012Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Publication number: 20120019918Abstract: 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: ApplicationFiled: October 3, 2011Publication date: January 26, 2012Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: James C. Dunphy, Stephen W. Marshall
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Publication number: 20110304596Abstract: 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: ApplicationFiled: August 22, 2011Publication date: December 15, 2011Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
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Patent number: 8031403Abstract: 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: GrantFiled: November 30, 2007Date of Patent: October 4, 2011Assignee: Texas Instruments IncorporatedInventors: James C. Dunphy, Stephen W. Marshall
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Patent number: 7710350Abstract: 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: GrantFiled: February 6, 2007Date of Patent: May 4, 2010Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Publication number: 20090251531Abstract: 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: ApplicationFiled: April 4, 2008Publication date: October 8, 2009Applicant: Texas Instruments IncorporatedInventors: Stephen W. Marshall, Michael David Mc Cormick, Henry William Neal, Stanford Porter Hudson
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Publication number: 20090009871Abstract: 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: ApplicationFiled: November 30, 2007Publication date: January 8, 2009Applicant: Texas Instruments IncorporatedInventors: James C. Dunphy, Stephen W. Marshall
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Publication number: 20080158263Abstract: 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: ApplicationFiled: December 28, 2006Publication date: July 3, 2008Applicant: Texas Instruments IncorporatedInventors: Sue Hui, Stephen W. Marshall
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Publication number: 20080151104Abstract: 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: ApplicationFiled: February 25, 2008Publication date: June 26, 2008Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
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Patent number: 7336290Abstract: 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: GrantFiled: January 7, 2004Date of Patent: February 26, 2008Assignee: Texas Instruments IncorporatedInventors: Stephen W. Marshall, Michael M. Allbright, Bill C. McDonald
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Patent number: 7330298Abstract: 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: GrantFiled: February 4, 2005Date of Patent: February 12, 2008Assignee: Texas Instruments IncorporatedInventors: William M. Bommersbach, Donald C. Whitney, Frederick C. Wedemeier, Roger S. Carver, Steven M. Penn, Stephen W. Marshall, Frank J. Poradish, Donald A. Powell
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Patent number: 7321458Abstract: 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: GrantFiled: October 30, 2006Date of Patent: January 22, 2008Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Patent number: 7173601Abstract: 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: GrantFiled: January 7, 2004Date of Patent: February 6, 2007Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Patent number: 7139040Abstract: 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: GrantFiled: December 29, 2003Date of Patent: November 21, 2006Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Patent number: 7130105Abstract: 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: GrantFiled: January 7, 2004Date of Patent: October 31, 2006Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Patent number: 7079095Abstract: 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: GrantFiled: June 4, 2003Date of Patent: July 18, 2006Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall
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Patent number: 6738104Abstract: 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: GrantFiled: February 23, 2001Date of Patent: May 18, 2004Assignee: Texas Instruments IncorporatedInventor: Stephen W. Marshall