| Patent application number | Description | Published |
|---|
| 20090115740 | INTERRUPT REDUCTION METHOD IN TOUCH SCREEN CONTROLLER - 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. | 05-07-2009 |
| 20100051354 | CAPACITIVE TOUCH SENSOR SYSTEM - 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. | 03-04-2010 |
| 20100053097 | CAPACITIVE TOUCH SENSOR SYSTEM - 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. | 03-04-2010 |
| 20100066701 | MULTIPLE TOUCH LOCATION IN A THREE DIMENSIONAL TOUCH SCREEN SENSOR - A touch screen capable of correctly identifying multiple touches employs multiple active line arrays oriented to provide multi-dimensional data. Three arrays of capacitance based active lines are each distinctly oriented to form a plurality of intersections. A first and second array are generally oriented perpendicularly while a third array is oriented to bisect the resulting matrix such that the active lines of the third array also intersect the existing vertices. As a result of a touch each active line array identifies the location of the touch from three distinct directions. Ambiguity from dual touch scenarios existing in dual array systems is removed by providing an additional reference. | 03-18-2010 |
| 20100328249 | CAPACITIVE-INDUCTIVE TOUCH SCREEN - A touch screen uses a combination of capacitive sensing and inductive sensing applied to the same sensor pattern. A capacitive sensor uses the electric field formed by the columns and rows of the sensor matrix. An inductive sensor uses the magnetic field formed by current flowing in column and row lines to induce an inductive pen. Using the same sensor lines, the magnetic field created by the oscillating inductive pen is detected. Both methods require no moving elements in the sensor and it is possible to combine both method of detections in the same sensor pattern. Using switch matrices, the sensor lines are operated in an open loop fashion for the capacitive detection mode, and are operated in a closed loop fashion for the inductive detection mode. | 12-30-2010 |
| 20110242048 | CAPACITIVE SENSING ANALOG FRONT END - 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. | 10-06-2011 |
| 20110242052 | MULTIPLE TOUCH LOCATION IN A THREE DIMENSIONAL TOUCH SCREEN SENSOR - A touch screen capable of correctly identifying multiple touches employs multiple active line arrays oriented to provide multi-dimensional data. Three arrays of capacitance based active lines are each distinctly oriented to form a plurality of intersections. A first and second array are generally oriented perpendicularly while a third array is oriented to bisect the resulting matrix such that the active lines of the third array also intersect the existing vertices. As a result of a touch each active line array identifies the location of the touch from three distinct directions. Ambiguity from dual touch scenarios existing in dual array systems is removed by providing an additional reference. | 10-06-2011 |
| 20120001643 | SENSING PHASE SEQUENCE TO SUPPRESS SINGLE TONE NOISE - A noise suppression method for a capacitance-to-voltage converter varies a sequence of sensing signal edges during a plurality capacitance measurements to produce a number of noise responses. The sensing signal edges are varied in a repetitive rising and falling edge pattern for each sequence. Three or more such sequences can be used, and the sequence with the highest noise is eliminated and the others are averaged. The noise suppression method can be implemented during calibration and then used for a number of normal acquisitions. The noise suppression method can be applied to capacitance-to-voltage converters having monitoring and integration phases. | 01-05-2012 |
