Touch Buffer Noise Mitigation for Input Devices

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Solution Overview

Problem

Current noise mitigation techniques in input devices are undesirable and fail to effectively improve usability under noisy conditions.

Innovation Solution

A processing system for input devices that includes a sensor module and a noise mitigation module, where the noise mitigation module uses a touch buffer to limit the reporting of positional information in high-noise modes by storing input object states and smoothing or filtering the data to reduce noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If noise mitigation techniques are employed in input devices, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveinput device performance under noisy conditionsVSAvoidcomplexity of noise mitigation system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The touch buffer stores multiple historical touch states (e.g., 8-16 samples) before generating a filtered output, performing noise mitigation in advance through data accumulation. This preliminary data collection allows the system to apply filtering algorithms that compare current touch positions with historical positions, effectively reducing noise impact while maintaining a relatively simple overall architecture.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The touch buffer acts as an intermediary component between the raw touch sensor and the output processing. It mediates the data flow by storing and conditioning touch position information, allowing noise filtering to occur in this intermediate stage without requiring complex real-time processing in the main signal path.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If touch buffer stores multiple input object states, then measurement precision is improved, but loss of time increases

Engineering Contradiction:

Improveaccuracy of positional informationVSAvoidtime delay in reporting positional information

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system uses a limited number of buffer samples (e.g., 8-16 touch states) rather than storing all historical data. This partial action approach provides sufficient noise filtering precision for practical applications while avoiding excessive time delays. The buffer size is optimized to balance filtering effectiveness with response time requirements.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically adjusts the buffer size and filtering parameters based on noise conditions and application requirements. By changing parameters such as the number of samples stored and the filtering algorithm intensity, the system can optimize the trade-off between measurement precision and time delay for different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9811213B2Systems and methods for input device noise mitigation via a touch buffer

Publication Date: 2017.11.07 SYNAPTICS INC

AI summary

A processing system for an input device includes a sensor module and a noise mitigation module. The sensor module includes sensor circuitry and is configured to drive a plurality of transmitter electrodes with transmitter signals, and receive, with a plurality of receiver electrodes, resulting signals comprising effects corresponding to the transmitter signals. The noise mitigation module is configured to determine positional information for a first input object in a sensing region of the input device based on the resulting signals and to report the positional information. The noise mitigation module includes a touch buffer configured to store a plurality of input object states corresponding to the first input object and is configured to limit, when in a high-noise mode, the reporting of positional information based on the plurality of input object states stored in the touch buffer.