Patents by Inventor David R Thomas

David R Thomas 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: 6711546
    Abstract: A coding scheme for digital audio signals. A method of coding a unary digital audio signal is provided for compressing a set of unary digital audio signal data comprising a succession of absolute amplitude values associated with respective sample periods of the digital audio signal, the absolute amplitude values being integers of positive or zero value, representing the number of speaker elements of a unary digital loudspeaker that are to be active in a sample period. The data is compressed by calculating the numerical difference between adjacent ones of the absolute amplitude values, thereby to convert the succession of absolute amplitude values into a corresponding succession of difference amplitude values. Each difference amplitude values is expressed as a sign bit and a plurality of data bits, representing the change in the number of speaker elements of a unary digital loudspeaker that are to be active in a given sample period relative to the immediately preceding sample period.
    Type: Grant
    Filed: July 14, 2000
    Date of Patent: March 23, 2004
    Inventor: David R. Thomas
  • Patent number: 6697642
    Abstract: Apparatus for a wireless communication network, comprises: a directional beam antenna, an antenna controller for directing said directional beam antenna in an optimum signal quality beam direction, and coding means operable at two or more coding rates, to switch between said rates responsive to said controller changing said antenna beam direction.
    Type: Grant
    Filed: July 19, 2000
    Date of Patent: February 24, 2004
    Assignee: Texas Instruments Incorporated
    Inventor: David R. Thomas
  • Publication number: 20040016109
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Application
    Filed: June 20, 2003
    Publication date: January 29, 2004
    Inventors: Naoto Kawamura, David R. Thomas, David J. Walter, Timothy L. Weber
  • Patent number: 6660175
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: December 9, 2003
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Naoto Kawamura, David R Thomas, David J Waller, Timothy L Weber
  • Patent number: 6641744
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Grant
    Filed: September 22, 2000
    Date of Patent: November 4, 2003
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Naoto Kawamura, David R Thomas, David J Waller, Timothy L Weber
  • Patent number: 6614466
    Abstract: To reduce the needed bandwidth of video communication system, a portion of the video image that differs from a preceding frame of the video image is predicted from the decompressed audio data with a model operating at both the transmitter and the receiver. The model accuracy is increased and the synchronisation enhanced by reducing the number of degrees of freedom of the model and by making the prediction of the next phoneme in a hierarchical manner.
    Type: Grant
    Filed: February 22, 2001
    Date of Patent: September 2, 2003
    Assignee: Texas Instruments Incorporated
    Inventor: David R. Thomas
  • Publication number: 20030137562
    Abstract: Described herein is a monolithic printhead formed using integrated circuit techniques. Thin film layers, including ink ejection elements, are formed on a top surface of a silicon substrate. The various layers are etched to provide conductive leads to the ink ejection elements. At least one ink feed hole is formed through the thin film layers for each ink ejection chamber. A trench is etched in the bottom surface of the substrate so that ink can flow into the trench and into each ink ejection chamber through the ink feed holes formed in the thin film layers. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers. A phosphosilicate glass (PSG) layer, providing an insulation layer beneath the resistive layers, is etched back from the ink feed holes and is protected by a passivation layer to prevent the ink from interacting with the PSG layer. Other layers may also be protected from the ink by being etched back.
    Type: Application
    Filed: January 30, 2003
    Publication date: July 24, 2003
    Inventors: Naoto A. Kawamura, Colin C. Davis, Timothy L. Weber, Kenneth E. Trueba, John Paul Harmon, David R. Thomas
  • Patent number: 6543884
    Abstract: Described herein is a monolithic printhead formed using integrated circuit techniques. Thin film layers, including ink ejection elements, are formed on a top surface of a silicon substrate. The various layers are etched to provide conductive leads to the ink ejection elements. At least one ink feed hole is formed through the thin film layers for each ink ejection chamber. A trench is etched in the bottom surface of the substrate so that ink can flow into the trench and into each ink ejection chamber through the ink feed holes formed in the thin film layers. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers. A phosphosilicate glass (PSG) layer, providing an insulation layer beneath the resistive layers, is etched back from the ink feed holes and is protected by a passivation layer to prevent the ink from interacting with the PSG layer. Other layers may also be protected from the ink by being etched back.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: April 8, 2003
    Assignee: Hewlett-Packard Company
    Inventors: Naoto A. Kawamura, Colin C. Davis, Timothy L. Weber, Kenneth E. Trueba, John Paul Harmon, David R. Thomas
  • Publication number: 20030034327
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Application
    Filed: September 4, 2002
    Publication date: February 20, 2003
    Inventors: Naoto Kawamura, David R. Thomas, David J. Waller, Timothy L. Weber
  • Patent number: 6517735
    Abstract: A monolithic inkjet printhead formed using integrated circuit techniques is described. A silicon substrate has formed on its top surface a thin polysilicon layer in the area in which a trench is to be later formed in the substrate. The edges of the polysilicon layer align with the intended placement of ink feed holes leading into ink ejection chambers. Thin film layers, including a resistive layer, are formed on the top surface of the silicon substrate and over the polysilicon layer. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers. A trench mask is formed on the bottom surface of the substrate. A trench is etched (using, for example, TMAH) through the exposed bottom surface of the substrate and to the polysilicon layer. The etching of the polysilicon layer exposes fast etch planes of the silicon. The TMAH then rapidly etches the silicon substrate along the etch planes, thus aligning the edges of the trench with the polysilicon.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: February 11, 2003
    Assignee: Hewlett-Packard Company
    Inventors: Kenneth E. Trueba, Charles C. Haluzak, David R. Thomas, Colby Van Vooren
  • Patent number: 6498939
    Abstract: An antenna network system comprises a server including a transmitter and an antenna, and a client including a receiver and a steerable antenna. There is also included a control path which is independently operable of the antennas for communicating control data between the server and client. The server is responsive to signal quality data communicated via the control path for steering at least one of the server antenna and client antenna in a direction for optimising the signal quality of communications transmitted between them.
    Type: Grant
    Filed: July 12, 2000
    Date of Patent: December 24, 2002
    Assignee: Texas Instruments Incorporated
    Inventor: David R. Thomas
  • Publication number: 20020154212
    Abstract: To reduce the needed bandwidth of video communication system, a portion of the video image that differs from a preceding frame of the video image is predicted from the decompressed audio data with a model operating at both the transmitter and the receiver. The model accuracy is increased and the synchronisation enhanced by reducing the number of degrees of freedom of the model and by making the prediction of the next phoneme in a hierarchical manner.
    Type: Application
    Filed: February 22, 2001
    Publication date: October 24, 2002
    Inventor: David R. Thomas
  • Publication number: 20020153346
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Application
    Filed: May 10, 2002
    Publication date: October 24, 2002
    Inventors: Naoto Kawamura, David R. Thomas, David J. Walter, Timothy L. Weber
  • Publication number: 20020134752
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Application
    Filed: May 10, 2002
    Publication date: September 26, 2002
    Inventors: Naoto Kawamura, David R. Thomas, David J. Waller, Timothy L. Weber
  • Publication number: 20020129495
    Abstract: A monolithic inkjet printhead formed using integrated circuit techniques is described. A silicon substrate has formed on its top surface a thin polysilicon layer in the area in which a trench is to be later formed in the substrate. The edges of the polysilicon layer align with the intended placement of ink feed holes leading into ink ejection chambers. Thin film layers, including a resistive layer, are formed on the top surface of the silicon substrate and over the polysilicon layer. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers. A trench mask is formed on the bottom surface of the substrate. A trench is etched (using, for example, TMAH) through the exposed bottom surface of the substrate and to the polysilicon layer. The etching of the polysilicon layer exposes fast etch planes of the silicon. The TMAH then rapidly etches the silicon substrate along the etch planes, thus aligning the edges of the trench with the polysilicon.
    Type: Application
    Filed: March 15, 2001
    Publication date: September 19, 2002
    Inventors: Kenneth E. Trueba, Charles C. Haluzak, David R. Thomas, Colby Van Vooren
  • Patent number: 6403995
    Abstract: A high performance unary digital loudspeaker system is disclosed; providing cost-effective and efficient performance, and providing the option to integrate multiple speaker elements or other related circuitry, and comprising a semiconductor substrate (102), an electrode (104) disposed upon the substrate, an insulator element (106) disposed upon the electrode forming a frame of material, an electrically conductive membrane (108) disposed upon the insulator element so as to form a chamber (110) between the electrode and the membrane, the membrane having a flexible support section (112) formed therein, and a control circuit (200) coupled (114, 116) to the membrane and the electrode, and adapted to provide a variable potential therebetween.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: June 11, 2002
    Assignee: Texas Instruments Incorporated
    Inventor: David R. Thomas
  • Patent number: 6336714
    Abstract: Described herein is a monolithic printhead formed using integrated circuit techniques. Thin film layers, including ink ejection elements, are formed on a top surface of a silicon substrate. The various layers are etched to provide conductive leads to the ink ejection elements. At least one ink feed hole is formed through the thin film layers for each ink ejection chamber. A trench is etched in the bottom surface of the substrate so that ink can flow into the trench and into each ink ejection chamber through the ink feed holes formed in the thin film layers. The trench completely etches away portions of the substrate near the ink feed holes so that the thin film layers form a shelf in the vicinity of the ink feed holes. In one embodiment, the shelf supports the ink ejection elements. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: January 8, 2002
    Assignee: Hewlett-Packard Company
    Inventors: Naoto A. Kawamura, Colin C. Davis, Timothy L. Weber, Kenneth E. Trueba, John Paul Harmon, David R. Thomas
  • Publication number: 20010048123
    Abstract: A high performance unary digital loudspeaker system is disclosed; providing cost-effective and efficient performance, and providing the option to integrate multiple speaker elements or other related circuitry, and comprising a semiconductor substrate (102), an electrode (104) disposed upon the substrate, an insulator element (106) disposed upon the electrode forming a frame of material, an electrically conductive membrane (108) disposed upon the insulator element so as to form a chamber (110) between the electrode and the membrane, the membrane having a flexible support section (112) formed therein, and a control circuit (200) coupled (114, 116) to the membrane and the electrode, and adapted to provide a variable potential therebetween.
    Type: Application
    Filed: May 21, 2001
    Publication date: December 6, 2001
    Inventor: David R. Thomas
  • Patent number: 6309054
    Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: October 30, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Naoto Kawamura, David R Thomas, David J Waller, Timothy L Weber
  • Patent number: 6305790
    Abstract: Described herein is a monolithic printhead formed using integrated circuit techniques. Thin film layers, including ink ejection elements, are formed on a top surface of a silicon substrate. The various layers are etched to provide conductive leads to the ink ejection elements. At least one ink feed hole is formed through the thin film layers for each ink ejection chamber. In one embodiment, there are more ink feed holes than ink ejection chambers, so that more than one ink feed hole provides ink to each ink ejection chamber. A trench is etched in the bottom surface of the substrate so that ink can flow into the trench and into each ink ejection chamber through the ink feed holes formed in the thin film layers. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: October 23, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Naoto A. Kawamura, Colin C. Davis, Timothy L. Weber, Kenneth E. Trueba, John Paul Harmon, David R. Thomas