Stephen W Marshall

US Patent:

6406148, Jun 18, 2002

Filed:

Dec 30, 1999

Appl. No.:

09/475731

Inventors:

Stephen W. Marshall - Richardson TX
James A. DeLong - Shady Shores TX
Andrea C. Harriman - Yardley PA

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G03D 2128

US Classification:

353 31, 348742, 348771, 353 99

Abstract:

A sequential color display system using three spatial light modulators and dichroic filters to sequentially provide a primary color light beam to a projection spatial light modulator. A set of dichroic filters separates a white light beam into primary colored light beams. Each primary colored light beam is modulated by a spatial light modulator to selectively allow it to travel to a second set of dichroic filters. The second set of dichroic filters recombines the primary color light beamsâonly one of which is typically active at any given timeâto form a sequential color light beam. A projection spatial light modulator selectively modulates the sequential color light beam to form a sequential color image projected onto an image plane.

US Patent:

6590549, Jul 8, 2003

Filed:

Dec 21, 1999

Appl. No.:

09/468980

Inventors:

Stephen W. Marshall - Richardson TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G09G 334

US Classification:

345 84, 345690, 345581

Abstract:

A micromirror capable of analog pulse width modulation, and method thereof A capacitor ( ) in each micromirror element stores a charge representative of one pixel of image data. A comparator ( ) compares the image data signal stored on the capacitor ( ) to a reference signal from a reference signal generator ( ). Depending on the results of the comparison, the address electrodes ( ) of the micromirror are biased to deflect the micromirror ( ). As either the image data charge stored on the capacitor ( ), or the reference voltage changes, the output of the comparator ( ) changes to alter the position of the micromirror ( ).

US Patent:

6738104, May 18, 2004

Filed:

Feb 23, 2001

Appl. No.:

09/792206

Inventors:

Stephen W. Marshall - Richardson TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04N 931

US Classification:

348743, 348742, 348771, 348536, 348270

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.

US Patent:

7079095, Jul 18, 2006

Filed:

Jun 4, 2003

Appl. No.:

10/453953

Inventors:

Stephen W. Marshall - Richardson TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G09G 3/34

US Classification:

345 84, 345690

Abstract:

A micromirror capable of analog pulse width modulation, and method thereof. A capacitor () in each micromirror element stores a charge representative of one pixel of image data. A comparator () compares the image data signal stored on the capacitor () to a reference signal from a reference signal generator (). Depending on the results of the comparison, the address electrodes () of the micromirror are biased to deflect the micromirror (). As either the image data charge stored on the capacitor (), or the reference voltage changes, the output of the comparator () changes to alter the position of the micromirror ().

US Patent:

7130105, Oct 31, 2006

Filed:

Jan 7, 2004

Appl. No.:

10/752982

Inventors:

Stephen W. Marshall - Richardson TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G02B 26/00

US Classification:

359291, 359290

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.

US Patent:

7139040, Nov 21, 2006

Filed:

Dec 29, 2003

Appl. No.:

10/747493

Inventors:

Stephen W. Marshall - Richardson TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04N 9/12
H04N 5/05
H04N 5/45
H03L 7/00
H02P 23/00
H02P 25/00
H02P 27/00
H02P 27/04

US Classification:

348743, 348270, 348524, 348536, 348537

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.

US Patent:

7173601, Feb 6, 2007

Filed:

Jan 7, 2004

Appl. No.:

10/753144

Inventors:

Stephen W. Marshall - Richardson TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G09G 3/34

US Classification:

345107, 345 81

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.

US Patent:

7194767, Mar 20, 2007

Filed:

Jun 28, 2002

Appl. No.:

10/185920

Inventors:

Kenneth C. Boydstun - Carrollton TX, US
Stephen L. Marshall - Ennis TX, US
Jun Chen - Lewisville TX, US

Assignee:

Sprint Communications Company L.P. - Overland Park KS

International Classification:

H04L 9/00
G06F 15/16

US Classification:

726 14, 726 1, 709225

Abstract:

A screened subnet for interconnecting an intranet to the Internet includes first and second subnets. A first firewall provides a first level of protection to a portion of the first subnet and to the second subnet while a second firewall provides a second level of protection to the second subnet. A secured utility VLAN provides utility services for the portion of the first subnet and/or the second subnet. The secured utility VLAN is coupled to the screened subnet such that it enjoys an additional level of protection relative to the subnets and/or the portion thereof which it serves. In various embodiments thereof, the screened subnet is configured to include a single, shared, secured utility VLAN for servicing both the portion of the first subnet and the second subnet, or a pair of discrete secured utility VLANs for respectively servicing the portion of the first subnet and the second subnet.