Elan Microelectronics Corporation

Macronix International Co., Ltd.

Chun-Chung Huang

Tsun-Min Wang

Te-Sheng Chiu

Chun-Yu Lin

I-Shu Lee

I-Hau Yeh

Tse-Chi Lin

Shih-Yuan Hsu

Chin-Cheng Yang

Chia-Hsing Lin

Yi-Hsin Tao

Yung-Tai Hung

Chi-Tung Huang

Chun-Fu Chen

Kun-Ming Tsai

Hsin-Shieh Tsai

Chun-yu Lin

Hung Nien

Chung-Han Cheng

Hung-Ming Huang

Chih-Hsien Teng

Hsiu-Ju Yang

Ching-Chung Wang

Yu-Hui Lin

Chi-Tein Yeh

A transconductance amplifier mirror circuit is connected to an electrode for sensing the capacitance of the electrode with reference to ground, or the capacitance between the electrode and another electrode. A voltage level change is produced on the electrode connected to the transconductance amplifier mirror circuit to cause the transconductance amplifier mirror circuit to supply charges to or drain charges from a charge calculation circuit. The charge amount variation is converted to a signal for calculating the sensed capacitance.

Circuit and method for sensing a capacitance

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.

Sensing method and calibration method for a capacitive touch panel

A capacitive touch panel controller has a memory and multiple driving signal output units. At least one transistor of each driving signal output unit and multiple transistors of the memory are fabricated by an identical semiconductor fabrication process so that the gate oxide layers of the transistors of the driving signal output unit and the memory are identical in thickness. As the transistor of each driving signal output unit and those of the memory are fabricated by a same high-voltage semiconductor fabrication process, the transistor of each driving signal output unit can be fabricated to provide a capacitive touch panel controller having high-voltage driving capability without using any high-voltage fabrication process and increasing the production cost. Due to the high-voltage driving, the SNR and anti-interference capability can be increased.

Capacitive touch panel controller and method of manufacturing the same

A control circuit and a control method for a capacitive touch panel are provided. Therein, while a scanning signal charges and discharges each trace on the capacitive touch panel, a signal in phase with the scanning signal is provided to traces adjacent to the scanned trace or a ground layer under the scanned trace so as to lower parasitic capacitances between the scanned trace and the ground layer or other traces, thereby decreasing a base capacitance of the capacitive touch panel and enhancing a sensing result of the control circuit as well as providing a shielding effect and reducing noise interference so that the capacitive touch panel has improved performance.

Control circuit and control method for capacitive touch panel

An equalized capacitive touchpad and a touch positioning method for a capacitive touchpad use an equalizer to correct a sensed value of a mutual capacitance between two sensing lines of the capacitive touchpad, to thereby offset the attenuation of the sensed value due to the impedance of the two sensing lines. Thus, the sensed values generated from different positions along a sensing line are equalized, and the touch positioning accuracy of the capacitive touchpad is improved.

Equalized capacitive touchpad and touch positioning method

A two-step detection for a capacitive touchpad to identify a real touch point first detects the self capacitances from multiple capacitance sensor traces of the capacitive touchpad to identify any touch point on the capacitive touchpad and then, if multiple touch points are detected, further detects the mutual capacitance at one of the detected touch points to identify whether it is a real touch point.

Detection method for a capacitive touchpad to identify a real touch point

A sensing method and circuit for a capacitive touch panel sense the capacitance variation of a lateral capacitor formed at the intersection of two traces of the capacitive touch panel, to distinguish a real point from a ghost point. A sensing cycle includes two non-overlapping clock phases. In the first clock phase, the voltages across the lateral capacitor and across a sensing capacitor are set. In the second clock phase, the voltage at a first, terminal of the lateral capacitor is changed, and a second terminal of the lateral capacitor is connected to a first terminal of the sensing capacitor, causing a voltage variation at a second terminal of the sensing capacitor. This voltage variation is used to determine whether the intersection is touched. The sensing method and circuit reflect the status of the lateral capacitor in real-time and prevent the location of the touch point from being misjudged.

Sensing circuit and method for a capacitive touch panel

A sensing method and circuit for a capacitive touch panel sense the capacitance variation of a lateral capacitor formed at the intersection of two traces of the capacitive touch panel, to distinguish a real point from a ghost point. A sensing cycle includes two non-overlapping clock phases. In the first clock phase, the voltages across the lateral capacitor and across a sensing capacitor are set. In the second clock phase, the voltage at a first terminal of the lateral capacitor is changed, and a second terminal of the lateral capacitor is connected to a first terminal of the sensing capacitor, causing a voltage variation at a second terminal of the sensing capacitor. This voltage variation is used to determine whether the intersection is touched. The sensing method and circuit reflect the status of the lateral capacitor in real-time and prevent the location of the touch point from being misjudged.

An electronic stylus emits an excitation signal to apply to a trace of a capacitive touchpad module near a touch point when the electronic stylus touches the capacitive touchpad module, so as to change a waveform of a charging/discharging signal in the trace, and depending on the waveform variation, the capacitive touchpad module can identify the touch point.

Electronic stylus, capacitive touchpad module, and apparatus for touch input

An equalized capacitive touchpad and a touch positioning method for a capacitive touchpad use an equalizer to correct a sensed value detected from a sensing line of the capacitive touchpad, to thereby offset the attenuation of the sensed value due to the impedance of the sensing line. Thus, the sensed values generated from different positions along a sensing line are equalized, and the touch positioning accuracy of the capacitive touchpad is improved.

Detector and detection method for a capacitive touchpad to identify a real touch point

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.

Boundary resolution improvement for a capacitive touch panel

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.

Front-end signal detector and method for improving noise immunity of a capacitive touch sensor

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.

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Hsinchu, Taiwan

Chun-Chung Huang