Touch Sensor Controller Frequency Switching for Noise-Aware Pointer Detection

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Solution Overview

Problem

Existing sensor controllers face challenges in efficiently managing electromagnetic noise levels in transmission signals to touch sensors, leading to potential frequency adjustments that may increase noise levels, thereby affecting detection accuracy.

Innovation Solution

A sensor controller that includes a transmission circuit to send signals in alternating periods for noise measurement and position detection, using a processor to measure noise levels and select optimal frequencies for transmission, adjusting frequencies based on noise measurements to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor controller analyzes frequency to identify noise components, then noise detection capability is improved, but circuit scale and manufacturing cost increase

Engineering Contradiction:

Improvenoise detection capabilityVSAvoidcircuit scale

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential noise measurement function by measuring noise levels at specific frequencies (first and second frequencies) rather than performing comprehensive frequency analysis. This selective measurement approach reduces circuit complexity while maintaining effective noise detection capability for the intended application.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of analyzing the entire frequency spectrum, the patent applies partial action by measuring noise at only two specific frequencies (first frequency for position detection and second frequency for noise measurement). This partial measurement suffices for the application requirements, avoiding the excessive complexity of full spectral analysis.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If the sensor controller changes transmission signal frequency based on noise analysis at one frequency, then noise avoidance is improved, but the controller may select frequencies with high noise levels

Engineering Contradiction:

Improvenoise avoidanceVSAvoidfrequency selection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by evaluating noise characteristics at multiple specific frequencies (first frequency for position detection and second frequency for noise measurement) rather than relying on a single frequency point. This multi-point assessment ensures more accurate frequency selection that truly reflects overall noise conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary noise measurement at the second frequency before finalizing the transmission frequency selection. This advance noise assessment allows the controller to proactively select optimal frequencies and avoid high-noise periods, improving both reliability and selection accuracy.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the sensor controller transmits signals continuously without noise measurement periods, then detection efficiency is improved, but electromagnetic noise levels increase

Engineering Contradiction:

Improvedetection efficiencyVSAvoidelectromagnetic noise levels

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the transmission cycle into distinct time periods: a first period for position detection and a second period for noise measurement. This temporal segmentation allows the system to maintain high detection efficiency during the first period while dedicating the second period to noise assessment, preventing noise accumulation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic action by alternating between position detection transmission and noise measurement transmission in a cyclic manner. This periodic structure ensures continuous operation for detection efficiency while incorporating regular noise measurement intervals to control electromagnetic noise levels.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20260016915A1Sensor controller, electronic device, and control method of sensor controller

Publication Date: 2026.01.15 WACOM CO LTD

AI summary

A sensor controller that controls a touch sensor detects a position of a passive pointer. The sensor controller includes a transmission circuit that transmits a transmission signal to the touch sensor in a plurality of third periods, each including a first period for measuring electromagnetic noise and a second period for detecting the position of the passive pointer and a processor configured to measure a level of electromagnetic noise at a frequency associated with the first period and a frequency associated with the second period, and select, as a scan frequency of the transmission signal in the second period, the frequency associated with the first period or the frequency associated with the second period according to a measurement result of the level of the electromagnetic noise at the frequency associated with the first period and the level of the electromagnetic noise at the frequency associated with the second period.