Transmitter Axis Projection for Capacitive Sensing Ghost Detection

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Solution Overview

Problem

Proximity sensor devices face challenges in accurately detecting input objects due to ghost detections and interference, particularly in capacitive sensing, which can lead to erroneous readings and reduced accuracy in determining positional information.

Innovation Solution

The implementation of a processing system that drives transmitter electrodes with specific signals and partitions receiver electrodes into subsets to generate a transmitter axis projection, allowing for improved capacitive sensing by distinguishing between actual input objects and noise, thereby enhancing the accuracy of positional information detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional capacitive sensing is used to detect input objects, then the sensing coverage is comprehensive, but ghost detections and interference increase leading to reduced accuracy

Engineering Contradiction:

Improveaccuracy of positional informationVSAvoidghost detections and interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The receiver electrodes are divided into multiple subsets, allowing the system to selectively drive different subsets and generate corresponding projections. This segmentation enables the system to isolate and eliminate ghost detections by comparing signals from different electrode subsets, thereby improving measurement precision without sacrificing comprehensive sensing coverage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts and removes harmful ghost detection signals from the capacitive sensing data by generating transmitter axis projections that represent only valid touch signals. This extraction process separates genuine input object detections from interference, resolving the contradiction between comprehensive sensing and accurate detection

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If all receiver electrodes are driven with transmitter signals, then complete capacitive sensing coverage is achieved, but processing complexity and computational load increase

Engineering Contradiction:

Improvecompleteness of capacitive sensingVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

By dividing receiver electrodes into subsets and processing them separately to generate individual transmitter axis projections, the system maintains complete sensing coverage while reducing the computational complexity of processing all electrodes simultaneously. Each subset can be processed independently, simplifying the overall processing architecture

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system drives only selected subsets of receiver electrodes with transmitter signals at different times, rather than driving all electrodes simultaneously. This partial action approach maintains the reliability of capacitive sensing by covering all regions through sequential processing, while significantly reducing the instantaneous processing complexity and computational load

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces ghost detections and interference, leading to more accurate capacitive sensing and improved usability of input devices by providing clearer capacitive images and projections that better represent touch signals without noise, thus enhancing the overall performance of proximity sensor devices.

Implementation Method 1

sensor circuitry configured to be coupled to transmitter electrodes and receiver electrodes. The sensor circuitry is configured to drive the transmitter electrodes with first transmitter signals and receive first resulting signals from the receiver electrodes

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentUS10402027B2Transmitter axis projection construction for capacitive sensing

Publication Date: 2019.09.03 SYNAPTICS INC

AI summary

Transmitter axis projection for capacitive sensing is disclosed. Transmitter axis projection includes having processing system. The processing system includes sensor circuitry configured to be coupled to transmitter electrodes and receiver electrodes. The sensor circuitry is configured to drive the transmitter electrodes with first transmitter signals and receive first resulting signals from the receiver electrodes, and drive only a first subset of the receiver electrodes with second transmitter signals and receive second resulting signals with the transmitter electrodes. The processing system further includes processing circuitry connected to the sensor circuitry and configured to partition the receiver electrodes into the first subset of receiver electrodes and a second subset of receiver electrodes, and generate a transmitter axis projection from the second resulting signals.