Abstract: In a movement detection method for multiple objects on a capacitive touchpad, the waveform of sensed values on the touchpad is monitored for its variation to determine respective movements of the objects on the touchpad, and various operational gestures are further determined exactly.

Abstract: A capacitive touch system uses at least two integrated circuits to simultaneously scan a touch panel, each scanning only a portion of traces of the touch panel, and a second integrated circuit to receive sensed data from the first integrated circuits. The sensed data contains parameters representing a sum of the sensed values of all traces in a direction that one of the first integrated circuits is in charge of scanning, a sum of products obtained by multiplying the sensed value of each trace in the direction that the one of the first integrated circuits scans by the order number of that trace, a number of fingers in the direction detected by the one of the first integrated circuits, and whether or not the sensed values of the first and last traces in the direction that the one of the first integrated circuits scans are zero.

Abstract: In a gesture detection method for a capacitive touchpad, various gesture operations are determined by detecting the touching on the touchpad, leaving from the touchpad, and moving on the touchpad.

Abstract: A method of controlling a cursor on a screen by using a touch device includes changing a display coordinate set of the cursor on the screen representative of an object according to a relative coordinate set with respect to movement of the object on the touch device, hiding the cursor from the screen when the object leaves the touch device for a duration in excess of a predetermined time, and when the cursor is not displayed on the screen and an object touches the touch device, computing an initial display coordinate set of the cursor on the screen according to an absolute coordinate set of the object on the touch device and a resolution ratio between the touch device and the screen. With this method, the cursor on the screen can be intuitively operated by using the touch device.

Abstract: In a gesture detection method for a touchpad, according to the present invention, various gestures such as tap, drag and double tap are determined by operating an object to touch on the touchpad, leave from the touchpad, and move on the touchpad.

Abstract: A passive architecture for scanning a touch panel includes a master IC and at least one passive touch IC connected to the master IC. The master IC generates a command to configure the scan parameters of the at least one passive touch IC, and the at least one passive touch IC scans the touch panel with the scan parameters in response to the command.

Abstract: Stimulus regions are defined based on the traces of a capacitive touch panel. A first signal is applied to a first trace in a first direction under a second signal applied to a second trace in a second direction to stimulate the second trace, to sense a stimulus region for an ADC value thereof. Calibration parameters for the traces are determined according to the ADC values of the traces without being touched, and are stored for later sensing the traces for position calculation and multi-finger calculation.

Abstract: A two dimensional dot code includes boundary dots, a direction dot and a code dot to regenerate an information therefrom. To decode the two dimensional dot code, the boundary dots and the direction dot are used to define coordinates of virtual code dots first and then, the code dot is compared with the coordinates of the virtual code dots. Thus, in order to retrieve the information represented by the two dimensional dot code, the position of the code dot can be rapidly determined without rotational correction of the image taken from the two dimensional dot code.

Abstract: A cursor control method using a touchpad triggers an automatic movement signal for a cursor when an object moves from a first defined region into a second defined region of a two-dimensional touch sensor, or when an object stays in the second defined region for a preset duration after it moves from the first defined region into the second defined region, and define the automatic movement signal with the direction identical to that of the object moving into the second defined region, so that the cursor will keep moving in its last moving direction.

Abstract: A circuit and method for trimming an internal oscillator of a USB device that generates a clock signal as a frequency source of the USB device detect an end of packet from an input data stream to initialize a counter, identify a token packet in the data stream to detect a start of frame token packet for the counter to carry out clock counting on the clock signal to thereby obtain a count value, and compare the count value with a reference value to determine a trimming code for trimming a clock frequency of the internal oscillator.

Abstract: A capacitive touch panel has a plurality of traces including a boundary trace, and a virtual trace is defined outward of the boundary trace and assigned with a virtual coordinate and a virtual capacitance for interpolation to position a touch point around the boundary of the capacitive touch panel, thereby eliminating the non-addressable region of the capacitive touch panel.

Abstract: A detect method of a capacitive touch panel alternately senses the traces of the capacitive touch panel to generate two series of fields, interpolates with the first fields to obtain interpolation fields having temporal coordinates identical to that of the second fields, and combines the second fields and the interpolation fields to generate reconstructed frames for coordinate calculation. Therefore, the capacitance sensing sequence of the traces is scheduled in a multi-field way to reduce the operation of the detector circuit of the capacitive touch panel.

Abstract: Methods are proposed for object positioning for an X-Y projected capacitive touch panel. In an embodiment, capacitance sensing under inphase excitation of traces is applied to set a base value when the capacitive touch panel is not touched and to obtain capacitances at intersections when the capacitive touch panel is touched, and the base value is compared with the measured capacitances to identify touch points. In other embodiments, X-Y projected sensing and all-point sensing are combined to reduce the amount of calculation and achieve the same positioning effect as an all-point capacitive touch panel.

Abstract: A detector circuit and detect method of a capacitive touch panel conditionally abort sensing of useless traces of the capacitive touch panel when the capacitive touch panel senses the traces thereof. For a selected trace, the trace voltage thereof is sampled to be compared with a threshold voltage. If the sampled voltage is lower than the threshold voltage, the sensing of this trace is aborted and thus the operation of the detector circuit is reduced to improve the performance of the capacitive touch panel.

Abstract: A detector circuit and detect method of a capacitive touch panel conditionally abort detection of useless traces of the capacitive touch panel when the capacitive touch panel detects the traces thereof. For a selected trace, first several digital values obtained by detecting the selected trace are compared with a threshold value to identify whether the selected trace is useful or not, and if the selected trace is identified useless, an abort signal is triggered to abort detection of the selected trace. Therefore, the performance of the capacitive touch panel is improved with higher frame rate and less power consumption.

Abstract: A front-end signal detector and a method for improving noise immunity of a capacitive touch sensor start counting a preset time to trigger an interrupt signal responsive to a positive or negative edge of a periodic noise, to break the path through which a demodulated signal comes into a low-pass filter, to prevent noise from accumulating in the low-pass filter, and consequently mitigate the influence of the noise on the detection signal generated by the front-end signal detector.

Abstract: A method for operation to a multi-touch environment screen by using a touchpad defines a movable control window on the screen, calculates an inter-window coordinate set of the object mapped from the touchpad to the control window according to an absolute coordinate set of the object on the touchpad and a resolution ratio between the touchpad and the control window when the touchpad is detected being touched, defines a cursor on the screen representative of the object according to the inter-window coordinate set, and changes a coordinate set of the cursor on the screen representative of the object according to a number of the object on the touchpad and movement thereof. This method allows a user to intuitively operate the screen by using the touchpad.

Abstract: A touch device for multi-touch environment generates a sensing signal in response to an object touch thereon, generates an event signal according to the sensing signal and a control signal, generates a cursor signal according to coordinate information of each touch point contained in the sensing signal and the event signal, and transmits the cursor signal and the event signal to the multi-touch environment. The cursor signal is used to control a cursor application to show a cursor at a screen for each touch point and changes appearances of the cursors. The cursors clearly inform a user of locations where his/her fingers correspond on the screen. By conducting touch events in the multi-touch environment through the cursors instead of actual fingers, the user can operate the touch device other than a touch screen in a multi-touch manner as operating a multi-touch screen.

Abstract: A sensing method for a capacitive touch panel includes charging a measure capacitor, setting the voltage across a mutual capacitor at the intersection of two traces of the capacitive touch panel, and then injecting partial charges of the measure capacitor into the mutual capacitor. When the intersection is touched, the capacitance value of the mutual capacitor is changed, and consequently the amount of charges injected into the mutual capacitor is changed. Hence, the voltage of the measure capacitor could be detected to determine whether or not the intersection is touched.

Abstract: A capacitive touchpad provides multiple operational modes including at least a key input mode, a handwriting input mode, and a mouse control mode. To switch the capacitive touchpad between the operational modes, a first pattern is defined as a mode switch for users to touch thereon. For each operational mode, specific second patterns are defined for indication of their corresponding functions, and several regions are defined corresponding to the positions of the second patterns to receive touch input from the second patterns.