Patent application number | Description | Published |
20100097078 | Noise Handling in Capacitive Touch Sensors - In a capacitive sensor of the type having X electrodes which are driven and Y electrodes that are used as sense channels connected to charge measurement capacitors, signal measurements are made conventionally by driving the X electrodes to transfer successive packets of charge to the charge measurement capacitors. However, an additional noise measurement is made by emulating or mimicking the signal measurement, but without driving the X electrodes. The packets of charge transferred to the charge accumulation capacitor are then indicative of noise induced on the XY sensing nodes. These noise measurements can be used to configure post-processing of the signal measurements. | 04-22-2010 |
20120235937 | Two-Dimensional Touch Sensors - In a touch sensor, as well as providing touch position data, additional data is provided on the shape of the touch. This is achieved by having sampling nodes on a finer mesh than the size of the actuating object, typically a finger, so each finger touch activates a group of adjacent nodes on the sensor. In this way, each touch has a shape formed by the activated nodes. The shape allows the touch sensor to report an angle with each touch and data indicating how elongate the touch is, preferably both together as a vector in which the direction of the vector gives the angle and the magnitude of the vector gives the ellipticity. For each frame of data collected from the sensor array, the sensor outputs an (x, y) coordinate of touch position and a further (x, y) coordinate of a shape vector. | 09-20-2012 |
20130147752 | Touch Sensor With Adaptive Touch Detection Thresholding - In one embodiment, a method includes receiving, by a controller coupled to a touch sensor, a plurality of signals from a plurality of sense electrodes, the plurality of signals indicative of an amount of capacitance between the touch sensor and an external object. The method further includes accessing a stored threshold value, determining a strength of a charge return path between the touch sensor and a ground, and adjusting the stored threshold value based on the determined strength of the charge return path. The threshold value indicates a threshold magnitude of the signals from the plurality of sense electrodes to process as a touch by the external object. | 06-13-2013 |
20130162583 | Enhanced Touch Detection Methods - In one embodiment, a method includes sending a first set of signals to a first set of lines of a touch sensor. The method also includes receiving a second set of signals on a second set of lines of the touch sensor in response to sending the first set of signals. The second set of lines are capacitively coupled to the first set of lines. The method includes sending a third set of signals and receiving a fourth set of signals. The fourth set of signals is capacitively generated based on the third set of signals. The method also includes determining a fifth set of signals by compensating the second set of signals based on the fourth set of signals and determining whether a touch occurred based on the fifth set of signals. | 06-27-2013 |
20130307569 | NOISE MEASUREMENT IN CAPACITIVE TOUCH SENSORS - In particular embodiments, an apparatus includes a charge-measurement capacitor having a first plate coupled to a second plate of a coupling capacitor and a non-transitory computer-readable storage medium embodying logic that is operable when executed to ground a first plate of the coupling capacitor; inject a pre-determined amount of charge onto the charge-measurement capacitor; and transfer an amount of charge accumulated on the second plate of the coupling capacitor to the first plate of the charge-measurement capacitor. The charge accumulated on the second plate of the coupling capacitor is due at least in part to noise. The logic is also operable when executed to determine, through a measured voltage across the charge-measurement capacitor, the amount of charge. | 11-21-2013 |
20140300376 | Noise Measurement in Capacitive Touch Sensors - In particular embodiments, an apparatus includes a charge-measurement capacitor having a first plate coupled to a second plate of a coupling capacitor and a non-transitory computer-readable storage medium embodying logic that is operable when executed to ground a first plate of the coupling capacitor; inject a pre-determined amount of charge onto the charge-measurement capacitor; and transfer an amount of charge accumulated on the second plate of the coupling capacitor to the first plate of the charge-measurement capacitor. The charge accumulated on the second plate of the coupling capacitor is due at least in part to noise. The logic is also operable when executed to determine, through a measured voltage across the charge-measurement capacitor, the amount of charge. | 10-09-2014 |
Patent application number | Description | Published |
20100097328 | Touch Finding Method and Apparatus - A method of determining touches from a data set output from a touch screen comprising an array of sensing nodes. The method comprises analyzing the dataset and identifies a node with a maximum signal value among all unassigned nodes, and, if present, assigns that node to a touch. A logical test is applied to each node that is a neighbor to the assigned node to determine if that node should also be assigned to the touch and the logical test is repeatedly applied to the unassigned neighbors of each newly assigned node until there are no more newly assigned nodes, or no more unassigned nodes, thereby assigning a group of nodes to the touch defining its area. This process can be repeated until all of the nodes of a touch panel are assigned to a touch. The method is ideally suited to implementation on a microcontroller. Therefore, although the kind of processing power being considered is extremely modest in the context of a microprocessor or digital signal processor, it is not insignificant for a microcontroller, or other low specification item, which has memory as well as processing constraints. | 04-22-2010 |
20100097329 | Touch Position Finding Method and Apparatus - In a touch sensor comprising a plurality of sensing nodes, the touch location in each dimension is obtained from the node at which the sum of the signal values assigned to the touch on either side of said node are equal or approximately equal. Each of the sensing nodes is replaced by a plurality of notional sensing nodes distributed around its respective sensing node over a distance corresponding to an internode spacing. Signal values 2, 6, 11, 5 and 2 have been obtained for the distribution of signal across the touch sensor. These signals are notionally split in equal spacings in the range covered by each node, each notional signal being shown with vertical tally sticks. The touch coordinate is then determined by finding the position of the median tally stick. Since there are 26 notional signals, each with a signal value of 1, the position of the median signal is between the 13th and 14th notional signals, as indicated by the thick arrow. This is a numerically simple method for obtaining touch coordinates at higher resolution than the resolution of the nodes ideally suited for implementation on a microcontroller. | 04-22-2010 |
20100097342 | Multi-Touch Tracking - A method of tracking multiple touches over time on a touch sensor, for example a capacitive touch screen. The method analyses first and second touch data sets from adjacent first and second time frames. First, the touch data sets are analyzed to determine the closest touch in the second time frame to each of the touches in the first time frame, and calculating the separation between each such pair of touches. Then, starting with the pair of touches having the smallest separation, each pair is validated until a pairing is attempted between touches for which the touch in the second time frame has already been paired. At this point, the as-yet unpaired touches from the first and second touch data sets are re-processed by re-applying the computations but only including the as-yet unpaired touches. This re-processing is iterated until no further pairings need to be made. The method avoids complex algebra and floating point operations, and has little memory requirement. As such it is ideally suited to implementation on a microcontroller. | 04-22-2010 |