Pixart Imaging Incorporated

Nxp B.v.

Other

University of California

Avago Technologies General IP (singapore) Pte. Ltd.

Ahbee 2, L.p., a California Limited Partnership

Vitali Souchkov

Rob Van Dalen

Kenneth D Brewer

Sarangan Narasimhan

Vladimir Faifer

Abhay Kumar Rai

Jeffrey Stone

Eugene Fukshansky

Robert Ritter

Padraig O'Mathuna

Victor Huang

Alexander Artjomov

Anatoli Skljarnov

According to one embodiment, there is provided a mutual capacitance touchscreen comprising a first set of electrically conductive traces arranged in rows or columns and a second set of electrically conductive traces arranged in rows or columns arranged at right angles with respect to the rows or columns of the first set, where the first and second sets of traces are electrically insulated from and interdigitated respecting one another, and gaps between the first and second sets of traces form boundaries between the first and second sets of traces that undulate and that are not straight or linear. Other embodiments of a mutual capacitance touchscreen are also disclosed, such as 'mini-diamond' sensor array patterns and sensor array patterns that may be manufactured at low cost.

Sensor patterns for mutual capacitance touchscreens

Ambient light is sensed for use in determining luminous flux. According to an example embodiment, ambient light is sensed using two light sensor arrangements that respectively respond differently to light of different relative wavelengths. The output of the sensors is nonlinearly combined to generate data indicative of the luminous flux. This luminous flux data is used to generate a control output for controlling an electronic display.

Light sensor arrangement

Disclosed herein are various embodiments of a capacitive touchscreen system which includes switchable charge acquisition circuits and corresponding charge integrator circuits for sensing mutual capacitances associated with a touchscreen. Various embodiments of the switchable charge acquisition circuits and corresponding charge integrator circuits provide lower power consumption, increased operational stability, substantially reduced integrated circuit area, and increased temperature stability.

Capacitive touchscreen system with switchable charge acquisition circuit

Disclosed herein are various embodiments of a capacitive touchscreen system that is capable of sensing simultaneous or near-simultaneous multiple finger touches made on a capacitive touchscreen. In one embodiment, drive-sense circuits operably connected to X and Y lines of the touchscreen may be interchangeably and selectably configured as either sense circuits or drive circuits by a drive/sense processor operably connected thereto.

Capacitive touchscreen system with drive-sense circuits

Disclosed herein are various embodiments of a capacitive touchscreen system that is capable of sensing simultaneous or near-simultaneous multiple finger touches made on a capacitive touchscreen. In one embodiment, drive and sense circuits operably connected to X and Y lines of the touchscreen may be interchangeably and selectably configured to drive and sense X and Y lines of the touchscreen, respectively, or drive and sense Y and X lines, respectively, of the touchscreen, through first and second multiplexers operating under the control of a drive/sense processor.

Capacitive touchscreen system with multiplexers

Disclosed herein are various embodiments of circuits and methods in a capacitive touchscreen system that eliminate the need to digitize an entire array of pixel signals obtained from a touchscreen. Instead, regions of interest, or projections of object or touch signal clusters, from touchscreenare employed to encode the coordinates or positions of objects or touches in an analog-to-digital converter (ADC). Encoding of object positions occurs during digitization of the analog signal clusters, which eliminates the need to separately digitize individual touchscreen signals. The disclosed circuits and methods reduce the number of signal processor channels that might otherwise be required, and lead to power consumption reduction in the capacitive touchscreen system, as well as in reducing the area required to implement the circuit architecture in an integrated circuit.

Capacitive touchscreen system with touch position encoding during analog-to-digital conversion

Disclosed herein are various embodiments of circuits and methods for reducing electromagnetic interference in mutual capacitance measurement or sensing systems, devices, components and methods such as capacitive touchscreens. Charge integrator circuits and switched capacitance filtering circuits are disclosed that improve the signal-to-noise ratio (or the ratio of a desired sensed mutual capacitance signal to an undesired EMI signal) in a capacitive sensor readout circuit without the need to increase the amplitude of the drive signal. The various embodiments of the charge integrator and switched capacitance filtering circuits described herein permit an improvement in noise immunity without requiring the excessive power levels typically associated with high amplitude drive circuitry, and moreover result in boosting signal-to-noise ratios during early stages of signal processing.

Reduction of electromagnetic interference in a capacitive touchscreen system

A pixel circuit uses two storage transistors to store two image signal samples, which include a reference signal produced by background noise of the pixel circuit and a signal produced by optical exposure of a photodetector and the background noise of the pixel circuit. An imaging integrated circuit uses a pixel circuit array, which may contain a number of such pixel circuits, and a charge acquisition circuit configured to read out image information obtained by the pixel circuit array. The charge acquisition circuit uses a first amplifier and a serially connected differential integrator that includes a second amplifier, a first differential integrator section and a second differential integrator section for the read out. A method for image information acquisition involves obtaining image information using the pixel circuit array and reading out the image information obtained by the pixel circuit array using the charge acquisition circuit.

Pixel circuit, imaging integrated circuit, and method for image information acquisition

Various embodiments of methods and devices for reducing capacitor mismatch errors in a pipeline analog-to-digital converter (ADC) are disclosed. A plurality of pipeline element circuits are provided, where each pipeline element circuit corresponds to a given bit of the pipeline ADC. A first pipeline element circuit is configured to digitize analog A and B capacitor mismatch error calibration voltages generated by all the pipeline element circuits of the ADC when the pipeline ADC is operating in a capacitor mismatch calibration phase. According to one embodiment, digital representations corresponding to A and B capacitor mismatch error calibration voltages for each of the pipeline element circuits are provided to an output shift register and summing circuit, which generates capacitor mismatch error correction codes corresponding to each bit and pipeline element circuit. The capacitor mismatch error correction codes are applied to each bit weight of the pipeline ADC after conversion of analog signals input to the pipeline ADC has been completed.

Capacitor mismatch error correction in pipeline analog-to-digital converters

Various embodiments of charge pump circuitry configured to generate output signals having first distortion signals superimposed thereon are disclosed. Demodulator input signals are also disclosed that have second distortion signals superimposed thereon. A synchronization signal is delivered to demodulator circuitry through at least first and second integer divider circuits and to charge pump circuitry through at least the first integer divider circuitry such that the first and second distortion signals have frequencies that are integer divisions of the synchronization frequency.

Charge pump frequency selection in touch screen sensor interface system

Various embodiments of methods and devices for reducing capacitor mismatch errors in a pipeline analog-to-digital converter (ADC) are disclosed, where in a pipeline element circuit and during a first phase, an input voltage provided by a sample-and-hold circuit is presented to first and second capacitors arranged in parallel in the pipeline element circuit. During a second phase, a second voltage corresponding to a second charge associated with the second capacitance is amplified and stored in the pipeline element circuit. During a third phase, the same input voltage of the first phase is again presented to the first and second capacitors, which are arranged in parallel in the pipeline element circuit. During a fourth phase a first voltage corresponding to the first charge is amplified and stored in the pipeline element circuit. After the first, second, third and fourth phases have been completed, digital representations of the first and second voltages are sent though corresponding registers for subsequent averaging along with digital representations of first and second voltages provided by other pipeline element circuits to produce a digital capacitor mismatch error corrected output.

Systems, devices and methods for capacitor mismatch error averaging in pipeline analog-to-digital converters

Various embodiments of capacitive touchscreen driving and sensing circuits are disclosed, where during a first phase the mutual capacitance between a given drive electrode and a given sense electrode is charged up to a first charge value corresponding substantially to a drive voltage times the mutual capacitance. During a second phase the charge storage capacitor is charged up to a value corresponding approximately to a difference in touchscreen capacitance network charges occurring during the first and second phases. The first and second phases do not overlap in time. Dark frame signals may also be acquired from the touchscreen to calibrate differences in touchscreen capacitance network charges.

Low voltage capacitive touchscreen charge acquisition and readout systems, circuits and methods for high system noise immunity

Various embodiments of readout circuits are disclosed where no touchscreen or touch panel recharge is required, and the amount of time available for signal acquisition is twice that relative to prior art touchscreen or touch panel readout circuits. Voltage offsets of the integrating amplifiers may be compensated for by notch filtering signals stored in readout circuit capacitors. Some embodiments of readout circuits disclosed herein permit large dynamic range capacitive touchscreen or touch panel signals to be processed, and do not require panel reset. Readout circuits are disclosed that permit doubling of the signal acquisition rate and pre-filtering of acquired touch panel signals for improved immunity from harmonic EMI. Signal acquisition and temporary storage may be carried out using the same capacitors in such readout circuits.

Capacitive touchscreen signal acquisition without panel reset

A light sensor and light sensing system to detect an intensity of incident light and an angle of incidence of the incident light. The light sensor includes a dielectric layer, a plurality of photo detectors coupled relative to the dielectric layer, and a plurality of stacks of opaque slats embedded within the dielectric layer. The dielectric layer is substantially transparent to the incident light. The photo detectors detect the incident light through the dielectric layer. The stacks of opaque slats are approximately parallel to an interface between the dielectric layer and the photo detectors. The stacks of opaque slats define light apertures between adjacent stacks of opaque slats. At least some of the stacks of opaque slats are arranged at a non-zero angle relative to other stacks of the opaque slats.

Growing community of inventors

Walnut Creek, CA, United States of America

Vitali Souchkov