Patent application number | Description | Published |
20090039902 | METHODS AND SYSTEMS FOR DETECTING A CAPACITANCE USING SIGMA-DELTA MEASUREMENT TECHNIQUES - Methods, systems and devices are described for detecting a measurable capacitance using sigma-delta measurement techniques. According to various embodiments, a voltage is applied to the measurable capacitance using a first switch. The measurable capacitance is allowed to share charge with a passive network. If the charge on the passive network is past a threshold value, then the charge on the passive network is changed by a known amount for a sufficient number of repetitions until the measurable capacitance can be detected. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to a button, slider, touchpad or other input sensor. | 02-12-2009 |
20090174416 | METHODS AND SYSTEMS FOR DETECTING A CAPACITANCE USING SWITCHED CHARGE TRANSFER TECHNIQUES - Methods, systems and devices are described for detecting a measurable capacitance using charge transfer techniques. According to various embodiments, a charge transfer process is performed for two or more times. During the charge transfer process, a pre-determined voltage is applied to the measurable capacitance, and the measurable capacitance is then allowed to share charge with a filter capacitance through a passive impedance that remains coupled to both the measurable capacitance and to the filter capacitance throughout the charge transfer process. The value of the measurable capacitance can then be determined as a function of a representation of a charge on the filter capacitance and the number of times that the charge transfer process was performed. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to an input sensor. | 07-09-2009 |
20090277696 | GRADIENT SENSORS - A capacitive sensing device for sensing a user input comprises a resistive sheet, a plurality of electrodes, at least one sensing node, and at least one charge integrator. The plurality of electrodes is disposed on a plurality of edge regions of the resistive sheet and configured for applying excitation voltages to the resistive sheet such that a substantially steady state voltage gradient is established on the resistive sheet. At least one of the sensing nodes is disposed on at least one of the plurality of edge regions of the resistive sheet and configured for sensing a resulting charge on the resistive sheet after establishment of the substantially steady state voltage gradient and a cessation of application of the excitation voltages. At least one of the charge integrators is coupled to the at least one sensing node and configured for measuring the resulting charge to produce a measurement. | 11-12-2009 |
20100148806 | METHODS AND SYSTEMS FOR DETECTING A CAPACITANCE USING SIGMA-DELTA MEASUREMENT TECHNIQUES - Methods, systems and devices are described for detecting a measurable capacitance using sigma-delta measurement techniques. According to various embodiments, a voltage is applied to the measurable capacitance using a first switch. The measurable capacitance is allowed to share charge with a passive network. If the charge on the passive network is past a threshold value, then the charge on the passive network is changed by a known amount for a sufficient number of repetitions until the measurable capacitance can be detected. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to a button, slider, touchpad or other input sensor. | 06-17-2010 |
20100315384 | UNTETHERED ACTIVE PEN AND A METHOD FOR COMMUNICATING WITH A CAPACITIVE SENSING DEVICE USING THE UNTETHERED ACTIVE PEN - A method for communicating with a capacitive sensing device using an untethered active pen. The method includes capacitively receiving a capacitive sensing signal at a capacitive receiving unit of the untethered active pen. The capacitive sensing signal is output from the capacitive sensing device. In addition, the method includes determining a first frequency and a first phase associated with the capacitive sensing signal. Moreover, the method includes transmitting at a second frequency and a second phase an amplified active pen signal at the capacitive sensing device from the untethered active pen. The amplified active pen signal has a second frequency and a second phase that correspond to the first frequency and the first phase. | 12-16-2010 |
20100327882 | CAPACITIVE SENSOR INTERFERENCE DETERMINATION - In a method of determining interference in a capacitance sensor, a signal is transmitted on a transmitter sensor channel of the capacitive sensor. The signal is received on a receiver sensor channel of the capacitive sensor, the receiver sensor channel being coupled with an amplifier. Behavior of the amplifier is examined for non-linearity to determine if a level of interference has been received by the receiver sensor channel in conjunction with receipt of the signal. | 12-30-2010 |
20110001494 | METHODS AND SYSTEMS FOR SIGMA DELTA CAPACITANCE MEASURING USING SHARED COMPONENTS - Methods, systems and devices are described for detecting a measurable capacitance using sigma-delta charge transfer techniques that can be implemented with many standard microcontrollers, and can share components to reduce device complexity and improve performance. In the various implementations of this embodiment, the passive network used to accumulate charge can be shared between multiple measurable capacitances. A switch or IO controlling the charge sharing and/or charge changing can also be shared Likewise, in various implementations a voltage conditioning circuit configured to provide a variable reference voltage can be shared between multiple measurable capacitances. Finally, in various implementations a guarding electrode configured to guard the measurable capacitances can be shared between multiple measurable capacitances. In each of these cases, sharing components can reduce device complexity and improve performance. | 01-06-2011 |
20120293190 | CAPACITIVE SENSOR INTERFERENCE DETERMINATION - A processing system for a capacitive input device is described. The capacitive input device includes a plurality of sensor electrodes configured to detect input objects in a sensing region. The processing system configured to transmit a signal on a transmitter sensor channel of the capacitive input device. The processing system is also configured to receive the signal on a receiver sensor channel of the capacitive input device, wherein the receiver sensor channel is coupled with an amplifier. The processing system is also configured to determine if a level of interference has been received by the receiver sensor channel in conjunction with receipt of the signal. | 11-22-2012 |