Abstract: Groove analysis in a device having a tactile input surface suited to detect more than one tactile input at a time. Using groove analysis allows a touch screen device a more robust and efficient algorithm for distinguishing between two different tactile inputs. The touch screen device may include a touch screen controller that includes an analysis circuit for determining grooves between touch inputs. Generally, when a touch input is received at the surface of a touch screen device, the touch screen may register touch strength signals at each of a plurality of touch regions. A groove may be generally defined as a touch region that exhibits a touch strength signal that is less than surrounding touch regions. Once all touch regions are analyzed by a groove analysis, various touch regions determined to grooves may be eliminated from a further analysis to determine the XY coordinates of actual touch inputs.

Abstract: An electronic device includes a flexible substrate. The flexible substrate includes a first portion having a plurality of first conductive lines formed thereon, a second portion having a plurality of second conductive lines formed thereon, and an intermediate portion mechanically coupling the first portion to the second portion. The intermediate portion is configured to permit folding so that the first and second portions can be arranged back-to-back or face-to-face such that plurality of the second conductive lines and plurality of first conductive lines are oriented so as to cross one another to thereby form a capacitive sensing panel. A single connector is mechanically coupled to the first portion or the second portion, and electrically coupled to the first portion and the second portion but not electrically coupling the first portion to the second portion.

Abstract: An electronic device may include a touchscreen having sensing capacitors, and readout circuitry. The readout circuitry may be configured to accumulate a sample set from each sensing capacitor, divide the sample set into sample subsets, remove a given sample subset when the given sample subset exceeds a threshold, and process remaining sample subsets for touch input.

Abstract: An electronic device may include a touchscreen having sensing capacitors, and readout circuitry. The readout circuitry may be configured to accumulate a sample set from each sensing capacitor, divide the sample set into sample subsets, remove a given sample subset when the given sample subset exceeds a threshold, and process remaining sample subsets for touch input.

Abstract: A charge sensing circuit generates a voltage in a sensing period that is indicative of sensed charge. The generated voltages are accumulated by an accumulator circuit over a number of sensing periods. A noise detection circuit senses when the voltage generated by the charge sensing circuit is outside of a boundary and generates a detection signal in response thereto. A control circuit, in response to the detection signal, controls the accumulator circuit to block accumulation of the voltages generated by the charge sensing circuit during at least the sensing period in which the detection signal is generated. An analog-to-digital converter circuit then converts an accumulated output voltage from the accumulator circuit to a digital value at the end of an accumulation time period that includes the sensing periods. The end of the accumulation time period is delayed by at least one sensing period in response to the detection signal.

Abstract: A video display includes a video display panel and a video display drive circuit configured to control a display on condition. A touch screen includes a touch screen panel (mounted on top of the video display panel) and a touch panel control and sense circuit configured to operate the touch screen panel in a self-capacitance mode. The touch panel control and sense circuit includes sense drive circuits configured to generate sense drive signals for application to sense lines of the touch screen panel. A controller controls actuation of the sense drive circuits so that the sense drive signals are synchronized to the display on condition. In an implementation, the leading edges of the sense drive signals are synchronized to the display on condition. In another implementation, a window is synchronized to the display on condition and the leading edges of the sense drive signals exhibit jitter within the window.

Abstract: A capacitive touch system generates data indicative of sensed capacitance measured at capacitive sensing nodes of a capacitive touch panel. A signal processing circuit is coupled to receive the data indicative of sensed capacitance from the capacitive touch system. The signal processing circuit operates to fit a parabolic curve to the data indicative of sensed capacitance. A sharpness of the fit parabolic curve is indicative of whether touch versus hover interaction with the capacitive touch panel. A touch detection threshold is as a function of the determined sharpness. The set touch detection threshold is then applied against the data indicative of sensed capacitance in order to make a touch detection.

Abstract: A capacitive sensing structure is formed from first electrically conductive sensor structures electrically coupled to each other in a first direction, and second electrically conductive sensor structures electrically coupled to each other in a second direction. Each first electrically conductive sensor structure includes a first diamond-shaped central region with electrically coupled first finger structures extending away therefrom. Each second electrically conductive sensor structure includes a second diamond-shaped central region with electrically conducting second finger structures extending away therefrom. Each second finger structure extends between two adjacent ones of the first finger structures. Floating structures may be included within an opening formed in the first diamond shaped central region. Floating structures may further be included between the first and second finger structures.

Abstract: A touch screen device is configured with rows of conductors capable of receiving wireless signals from a stylus. When the stylus touches the touch screen, the stylus emits multiple wireless signals in different directions. The conductors receiving the emitted wireless signals provide the signals to circuitry that filters, amplifies, and digitizes the wireless signals, as received at each conductor. The magnitude of each conductor's received wireless signal is computed, and the computed magnitudes are used to determine the location of the stylus on the touch screen surface. The stylus is assumed to be closer to conductors receiving stronger signals than those receiving weaker signals.

Abstract: An ITO sensor design and method for making the same is optimized to minimize noise from an LCD. The design includes a two layer sensor design having a transmitter line (Tx) placed in a first layer and a receiver line (Rx) placed in a second layer in a diamond-shaped pattern. The diamond shape maximizes the sensitivity of the sensor.

Abstract: A capacitive touch system generates data indicative of sensed capacitance measured at capacitive sensing nodes of a capacitive touch panel. A signal processing circuit is coupled to receive the data indicative of sensed capacitance from the capacitive touch system. The signal processing circuit operates to fit a parabolic curve to the data indicative of sensed capacitance. A sharpness of the fit parabolic curve is indicative of whether touch versus hover interaction with the capacitive touch panel. A touch detection threshold is as a function of the determined sharpness. The set touch detection threshold is then applied against the data indicative of sensed capacitance in order to make a touch detection.

Abstract: A video display includes a video display panel and a video display drive circuit configured to control a display on condition. A touch screen includes a touch screen panel (mounted on top of the video display panel) and a touch panel control and sense circuit configured to operate the touch screen panel in a self-capacitance mode. The touch panel control and sense circuit includes sense drive circuits configured to generate sense drive signals for application to sense lines of the touch screen panel. A controller controls actuation of the sense drive circuits so that the sense drive signals are synchronized to the display on condition. In an implementation, the leading edges of the sense drive signals are synchronized to the display on condition. In another implementation, a window is synchronized to the display on condition and the leading edges of the sense drive signals exhibit jitter within the window.

Abstract: An in-cell touchscreen panel includes columns of transmit electrodes and rows of sensing electrodes, wherein each row of sensing electrodes comprises a first subset of sensing electrodes coupled to control circuitry via a first subset of receiving traces and a second subset of sensing electrodes coupled to the control circuitry via a second subset of receiving traces. To enable multi-touch functionality, the in-cell touchscreen panel operates in a scanning mode where capacitance is measured at each node where the sensing electrodes intersect the transmit electrodes. During the scanning mode, the control circuitry senses the first and second subsets of receiving traces while applying drive signals to pairs of transmit electrodes. After a drive signal has been applied to each of the transmit electrodes, each of the nodes are measured to detect a capacitance. This capacitance is indicative of a user touch on the in-cell touchscreen panel.

Abstract: A capacitive sensing analog front end for a touchscreen system having an improved signal-to-noise ratio includes a capacitance-to-voltage converter having an input for coupling to an external sampling capacitor, a summer having a first input coupled to an output of the capacitance-to-voltage converter, a low pass filter having an input coupled to an output of the summer and an output for providing an output signal; and a sample-and-hold circuit having an input coupled to the output of the low pass filter and an output coupled to a second input of the summer. The signal-to-noise ratio of the touchscreen system is improved by extracting the DC shift of a touch signal during a monitoring period and then subtracting the DC shift before integrating the touch signal.

Abstract: Groove analysis in a device having a tactile input surface suited to detect more than one tactile input at a time. Using groove analysis allows a touch screen device a more robust and efficient algorithm for distinguishing between two different tactile inputs. The touch screen device may include a touch screen controller that includes an analysis circuit for determining grooves between touch inputs. Generally, when a touch input is received at the surface of a touch screen device, the touch screen may register touch strength signals at each of a plurality of touch regions. A groove may be generally defined as a touch region that exhibits a touch strength signal that is less than surrounding touch regions. Once all touch regions are analyzed by a groove analysis, various touch regions determined to grooves may be eliminated from a further analysis to determine the XY coordinates of actual touch inputs.

Abstract: A touch screen device is configured with rows of conductors capable of receiving wireless signals from a stylus. When the stylus touches the touch screen, the stylus emits multiple wireless signals in different directions. The conductors receiving the emitted wireless signals provide the signals to circuitry that filters, amplifies, and digitizes the wireless signals, as received at each conductor. The magnitude of each conductor's received wireless signal is computed, and the computed magnitudes are used to determine the location of the stylus on the touch screen surface. The stylus is assumed to be closer to conductors receiving stronger signals than those receiving weaker signals.

Abstract: A digital filter receives a sequence of input signal values. A filtering block performs a filtering operation on sequence of input signal values that is controlled by filter coefficients. A control block also receives the sequence of input signal values. The control block evaluates detected changes over time with respect to the sequence of input signal values and selects values for the filter coefficients based on the detected changes. The detected change over time provides an indication of the whether the sequence of input signal values is changing signal state. If so, the filter coefficients are selected to emphasize signal response time over signal noise filtering for the filtering operation. Otherwise, the filter coefficients are selected to emphasize signal noise filtering over signal response time for the filtering operation.

Abstract: A touch controller processes a captured data frame and detects the presence of touch points in the data frame. The data frame includes a plurality of digital capacitance values organized as groups of sense line data and the touch controller determines for each digital capacitance value in a group of sense line data the difference between the digital capacitance value and an associated no-touch threshold to generate a baseline delta value for each digital capacitance value in the group. The touch controller selects the minimum baseline delta and adjusts each digital capacitance value in the group by the minimum baseline delta to generate adjusted sense line data. The touch control generates adjusted sense line data for each group of sense line data in the data frame and thereafter processes the groups of adjusted sense line data to detect the presence of touch points in the data frame.

Abstract: A method of matrix sensing using delay-based capacitance sensing, including using X-axis lines as active lines for capacitance measurements and using Y-axis lines as a disturbance to identify the location of a touch in a key matrix is disclosed. A sensing signal is applied to the X-axis lines, and a disturbance signal is applied to the Y-axis lines. If a location is touched, cross-capacitance is reduced, which is measured by sweeping data along the X-axis lines.

Abstract: Integration of a FIFO memory, FIFO threshold and a timer, along with the other components of a touch screen system allows the number of interrupts to the touch screen controller to be reduced while allowing all point data to be acquired and preserved. In the first touch-detect event, an interrupt is issued to inform the host. The touch screen controller then automatically acquires data as long as touch is detected without host intervention. A FIFO threshold defines the minimum number of data points in FIFO memory before it issues an interrupt to inform the host that data is ready to be fetched. The timer is started once touch is detected. On every single data acquired, the timer is reset. In the event where touch is no longer detected, the timer keeps on counting until the time-up limit is reached. In this event, the touch screen controller will issue an interrupt informing the host the pen is lifted. The host then checks whether there is still data left in FIFO memory to be read.