Patents by Inventor Christopher A. Ludden
Christopher A. Ludden 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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Publication number: 20150123944Abstract: Embodiments of the invention generally provide an input device with display screens that periodically update (refresh) the screen by selectively driving common electrodes corresponding to pixels in a display line. In general, the input devices drive each electrode until each display line (and each pixel) of a display frame is updated. In addition to updating the display, the input device may perform capacitive sensing using the display screen as a proximity sensing area. To do this, the input device may interleave periods of capacitive sensing between periods of updating the display based on a display frame. For example, the input device may update the first half of display lines of the display screen, pause display updating, perform capacitive sensing, and finish updating the rest of the display lines. Further still, the input device may use common electrodes for both updating the display and performing capacitive sensing.Type: ApplicationFiled: January 12, 2015Publication date: May 7, 2015Inventors: Jeffrey S. LILLIE, John CHILDS, Christopher A. LUDDEN, Thomas MACKIN, Petr SHEPELEV
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Patent number: 9007343Abstract: Embodiments described herein mitigate the effect of a coupling capacitance between a sensor electrode in a touch sensor and a display electrode in a display screen. An input device, which includes the touch sensor and display screen, may transmit a guarding signal on the display electrodes when performing capacitive sensing. In one embodiment, the guarding signal may have similar characteristics as a modulated signal (e.g., similar amplitude and/or phase) driven on the sensor electrode to detect interaction between the input device and an input object. By driving a guarding signal that is similar to the modulated signal onto the display electrodes, the voltage difference between the sensor electrode and display electrode remains the same. Accordingly, the coupling capacitance between the sensor electrode and the display electrode does not affect a capacitance measurement used to detect the user interaction.Type: GrantFiled: October 30, 2013Date of Patent: April 14, 2015Assignee: Synaptics IncorporatedInventor: Christopher A. Ludden
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Publication number: 20150091842Abstract: Embodiments described herein include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, all of which include a grid electrode for improved absolute sensing. Other embodiments include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, wherein the capacitive sensing device includes a matrix of discrete sensor electrodes.Type: ApplicationFiled: September 30, 2013Publication date: April 2, 2015Applicant: SYNAPTICS INCORPORATEDInventors: Petr SHEPELEV, Christopher A. LUDDEN, Jeffrey LUKANC, Stephen L. MOREIN, Greg P. SEMERARO, Joseph Kurth REYNOLDS
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Publication number: 20150091843Abstract: Embodiments described herein mitigate the effect of a coupling capacitance between a sensor electrode in a touch sensor and a display electrode in a display screen. An input device, which includes the touch sensor and display screen, may transmit a guarding signal on the display electrodes when performing capacitive sensing. In one embodiment, the guarding signal may have similar characteristics as a modulated signal (e.g., similar amplitude and/or phase) driven on the sensor electrode to detect interaction between the input device and an input object. By driving a guarding signal that is similar to the modulated signal onto the display electrodes, the voltage difference between the sensor electrode and display electrode remains the same. Accordingly, the coupling capacitance between the sensor electrode and the display electrode does not affect a capacitance measurement used to detect the user interaction.Type: ApplicationFiled: October 30, 2013Publication date: April 2, 2015Applicant: SYNAPTICS INCORPORATEDInventor: Christopher A. LUDDEN
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Publication number: 20150091849Abstract: Embodiments of the disclosure generally provide an integrated control system having an integrated controller that is configured to provide both display updating signals to a display device and a capacitive sensing signal to a sensor electrode that is disposed within the integrated input device. The internal and/or external signal routing configurations described herein can be adapted to reduce signal routing complexity typically found in conventional devices and reduce the effect of electrical interference created by the capacitive coupling formed between the display routing, capacitive sensing routing and/or other components within the integrated control system. Embodiments can also be used to reduce electromagnetic interference (EMI) on the display and touch sensing signals received, transmitted and processed within the integrated control system.Type: ApplicationFiled: March 19, 2014Publication date: April 2, 2015Applicant: SYNAPTICS INCORPORATEDInventor: Christopher A. LUDDEN
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Publication number: 20150091587Abstract: Embodiments described herein include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device. In one embodiment, the display device includes a plurality of sensor electrodes, a field shaping electrode, and a processing system. Each sensor electrode includes at least one common electrode. Dimensions of each sensor electrode correspond to dimension of pixel elements of the display device. The field shaping electrode is disposed between two of the plurality of sensor electrodes. Dimensions of the field shaping electrode correspond to the dimension of pixel elements of the display device. The field shaping electrode is laterally spaced apart from the two sensor electrodes a distance corresponding to dimensions of the pixel elements. The processing system is coupled to the sensor electrodes and the field shaping electrode.Type: ApplicationFiled: September 30, 2013Publication date: April 2, 2015Applicant: SYNAPTICS INCORPORATEDInventors: Petr SHEPELEV, Christopher A. LUDDEN, Jeffrey LUKANC, Stephen L. MOREIN
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Patent number: 8970537Abstract: Embodiments described herein include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, all of which include a grid electrode for improved absolute sensing. Other embodiments include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, wherein the capacitive sensing device includes a matrix of discrete sensor electrodes.Type: GrantFiled: January 17, 2014Date of Patent: March 3, 2015Assignee: Synaptics IncorporatedInventors: Petr Shepelev, Christopher A. Ludden, Jeffrey Lukanc, Stephen L. Morein, Greg P. Semeraro, Joseph Kurth Reynolds
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Publication number: 20150042599Abstract: An electrode matrix that is used for capacitive sensing may be integrated into a display panel of an input device. In one embodiment, source drivers may be mounted on the display panel which drive the display signals and capacitive sensing signals into the display panel. In one embodiment, the capacitive sensing signals may be routed on wires or lines that are interleaved on the same layer as the source lines used for setting a voltage on the pixels in the display panel during display updating. Using the interleaved wires, the source drivers may drive the capacitive sensing signals in parallel to a plurality of the electrodes in the matrix in a predefined pattern that spans one or more touch cycles.Type: ApplicationFiled: December 20, 2013Publication date: February 12, 2015Applicant: SYNAPTICS INCORPORATEDInventors: Jeffrey LUKANC, Stephen L. MOREIN, Christopher A. LUDDEN, Greg P. SEMERARO, Joseph Kurth REYNOLDS, Petr SHEPELEV
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Publication number: 20150042600Abstract: An electrode matrix that is used for capacitive sensing may be integrated into a display panel of an input device. In one embodiment, source drivers may be mounted on the display panel which drive the display signals and capacitive sensing signals into the display panel. In one embodiment, the capacitive sensing signals may be routed on traces or lines that are interleaved on the same layer as the source lines used for setting a voltage on the pixels in the display panel during display updating. Using the interleaved traces, the source drivers may drive the capacitive sensing signals in parallel to a plurality of the electrodes in the matrix in a predefined pattern that spans one or more sensing cycles.Type: ApplicationFiled: December 20, 2013Publication date: February 12, 2015Applicant: SYNAPTICS INCORPORATEDInventors: Jeffrey LUKANC, Stephen L. MOREIN, Christopher A. LUDDEN, Greg P. SEMERARO, Joseph Kurth REYNOLDS, Petr SHEPELEV, Thomas MACKIN
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Publication number: 20150002407Abstract: Embodiments described herein synchronize a switching frequency of switched power supplies with timing events associated with updating a display screen or performing touch sensing. For example, a touch event may be the time needed for a touch controller to scan a plurality of sensing electrodes. Because noise is introduced each time switched power supplies switch between different stages, the touch controller may instruct a power management controller to switch between the stages (i.e., adjust the switching frequency) at the same time during each touch event. Even though the switched power supplies are permitted to introduce noise into the touch system, the noise happens at the same time during each touch event. Accordingly, the effect of the noise is the same for each touch event and is cancelled out. A similar process may be used for synchronizing the switching frequency to display events.Type: ApplicationFiled: June 28, 2013Publication date: January 1, 2015Inventors: Imre KNAUSZ, Christopher LUDDEN, Thomas MACKIN, Murat OZBAS, Mark PUDE
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Publication number: 20140002410Abstract: Circuit architecture is provided to allow for flexible touch transmit signaling of a display device having an integrated capacitive sensing device. The circuit architecture includes an addressable selection module for non-sequentially selecting a plurality of transmitter electrodes to be driven for capacitive sensing. The circuit architecture supports a high voltage drive scheme that provides voltage sources for capacitive sensing and for updating the display device. The circuit architecture also supports a low voltage (logic level) drive scheme that provides a logic signal to be used by TFT circuitry to drive voltage signals for capacitive sensing and for updating the display device.Type: ApplicationFiled: June 29, 2012Publication date: January 2, 2014Applicant: Synaptics IncorporatedInventors: Jeffrey Lillie, John Childs, Christopher Ludden
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Publication number: 20130342481Abstract: Embodiments of the present invention generally provide a processing system for a display device having an integrated sensing device. The processing system includes a driver module coupled to a plurality of transmitter electrodes. Each transmitter electrode includes one or more common electrodes configured for display updating and input sensing. The driver module is configured for selecting a first display line set for display updating during a first display update period and driving the first display line set for display updating during the first display update period. The driver module is further configured for driving one or more transmitter electrodes of the plurality of transmitter electrodes for input sensing during a non-display update period and selecting a second display line set for display updating during a restart period.Type: ApplicationFiled: March 14, 2013Publication date: December 26, 2013Inventors: Jeffrey A. SMALL, Petr SHEPELEV, Christopher LUDDEN, Thomas MACKIN, Stephen MOREIN
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Patent number: 8416173Abstract: A method is arranged to process a frame for an LCD with a modified polarity pattern. The pattern employs a polarity reversal scheme that results in line inversion and/or dot inversion patterns that are observable by pixel locations within the frame. The drive polarity for the column drivers in the LCD is toggled according to the modified polarity pattern. The scanning sequence for each row on the display is modified for cooperation with the pattern. A first subframe is scanned during a first interval while applying a first set of drive polarities. A second subframe is scanned during a second interval that is non-overlapping with the first time interval. The application of the method enables the column drivers in the LCD to operate with reduced power while retaining the benefits of line and dot inversion techniques.Type: GrantFiled: September 5, 2006Date of Patent: April 9, 2013Assignee: National Semiconductor CorporationInventor: Christopher A. Ludden
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Publication number: 20130057512Abstract: Embodiments of the invention generally provide an input device with display screens that periodically update (refresh) the screen by selectively driving common electrodes corresponding to pixels in a display line. In general, the input devices drive each electrode until each display line (and each pixel) of a display frame is updated. In addition to updating the display, the input device may perform capacitive sensing using the display screen as a proximity sensing area. To do this, the input device may interleave periods of capacitive sensing between periods of updating the display based on a display frame. For example, the input device may update the first half of display lines of the display screen, pause display updating, perform capacitive sensing, and finish updating the rest of the display lines. Further still, the input device may use common electrodes for both updating the display and performing capacitive sensing.Type: ApplicationFiled: September 7, 2012Publication date: March 7, 2013Applicant: Synaptics IncorporatedInventors: Jeffrey Lillie, John Childs, Christopher Ludden, Thomas Mackin, Petr Shepelev
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Publication number: 20130021229Abstract: An apparatus is provided, which includes a driving circuit. The driving circuit includes a gamma reference source and a liquid crystal display (LCD) source driver circuit. A first resistor string is provided. A plurality of digital-to-analog converters (DACs) are provided, where each DAC is coupled to the first resistor string. An output circuit having a second resistor string is provided so as to output a plurality of reference voltages. The LCD source driver circuit is coupled to the output circuit of the gamma reference source. The source driver is configured to receive the plurality of reference voltages, wherein the plurality of reference voltages are arranged in a first sequence during a positive polarity cycle and are arranged in a second sequence during a negative polarity cycle. The fifth sequence is an inverse of the fourth sequence.Type: ApplicationFiled: July 27, 2012Publication date: January 24, 2013Applicant: National Semiconductor CorporationInventors: Christopher Ludden, Imre Knausz
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Patent number: 8072394Abstract: Data enable learning is provided for a video display driver in which a data enable signal and pixel clock exclusive of their associated horizontal and vertical synchronization signals for a digital video signal are used to facilitate generating of signals corresponding to the associated horizontal and vertical synchronization signals.Type: GrantFiled: May 28, 2008Date of Patent: December 6, 2011Assignee: National Semiconductor CorporationInventors: Christopher A. Ludden, John S. Childs
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Patent number: 7843422Abstract: An ambient light compensation circuit for controlling a backlight brightness is provided. The circuit automatically adjusts the LCD backlight brightness based on a reading of the ambient light. The circuit includes a non-linear ADC and a backlight control circuit. The non-linear ADC provides a digital signal from a photodiode signal. The backlight control circuit adjusts the brightness of the backlighting based on the digital signal. The brightness adjustment is performed gradually, e.g., one significant bit of the digital signal per second.Type: GrantFiled: November 29, 2005Date of Patent: November 30, 2010Assignee: National Semiconductor CorporationInventors: Christopher A. Ludden, Imre Knausz
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Publication number: 20100277505Abstract: A system comprising a display screen configured for displaying images, a touch sensor having a sensing region, a host processing system and a touch screen control system. The touch screen control system comprising touch sensor control circuitry configured to operate the touch sensor and display control circuitry configured to operate the display screen. The display circuitry comprising a first memory configured to hold a primary image and a second memory configured to hold a secondary image and display refresh circuitry. The display refresh circuitry configured to update the display screen, and in response to the user input and without requiring intervention by the host processing system, generate a blended image comprising the primary image and the secondary image, and update the display screen with the blended image.Type: ApplicationFiled: April 29, 2010Publication date: November 4, 2010Inventors: Christopher A. Ludden, Thomas A. Mackin, Shawn P. Day, David W. Gillespie
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Publication number: 20080303767Abstract: Voltage generator circuitry for providing a plurality of voltages for use in gamma compensation of a video signal.Type: ApplicationFiled: May 28, 2008Publication date: December 11, 2008Applicant: National Semiconductor CorporationInventors: Christopher Ludden, Imre Knausz
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Publication number: 20080303750Abstract: Data enable learning is provided for a video display driver in which a data enable signal and pixel clock exclusive of their associated horizontal and vertical synchronization signals for a digital video signal are used to facilitate generating of signals corresponding to the associated horizontal and vertical synchronization signals.Type: ApplicationFiled: May 28, 2008Publication date: December 11, 2008Applicant: National Semiconductor CorporationInventors: Christopher Ludden, John Childs