Touch Sensor Frequency Allocation to Avoid Display Noise

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Solution Overview

Problem

Existing display devices face challenges in maintaining high sensing performance for touch inputs while managing power consumption, especially as the size of the display increases.

Innovation Solution

Implementing frequency-division multiplexing (FDM) and frequency allocation for driving the input sensor, which involves using a sensor controller to provide transmission signals with different frequencies to transmission electrodes, forming mutual capacitors with reception electrodes, and ensuring these frequencies do not overlap with display noise frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If frequency-division multiplexing is implemented to improve sensing performance, then sensing performance is improved, but device complexity increases

Engineering Contradiction:

Improvesensing performanceVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum into multiple distinct frequency channels, assigning each transmission electrode a unique frequency. This segmentation allows simultaneous operation of multiple electrodes without interference, improving sensing performance while managing complexity through systematic frequency allocation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic transmission of signals at different frequencies to successive transmission electrodes. By using periodic action with frequency division, the system achieves continuous monitoring across all electrodes while maintaining manageable device complexity through rhythmic, predictable signal patterns

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If transmission signals with different frequencies are used to improve sensing performance, then power consumption increases

Engineering Contradiction:

Improvesensing performanceVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic transmission of frequency-divided signals to transmission electrodes, allowing the system to achieve comprehensive sensing coverage while reducing average power consumption compared to continuous high-frequency signaling. The periodic nature enables energy-efficient operation by activating electrodes in sequence rather than simultaneously

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the frequency parameter of transmission signals to optimize sensing performance. By carefully selecting frequency values that avoid overlap with display noise, the system achieves high sensing accuracy while maintaining reasonable power consumption levels through efficient frequency utilization

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If transmission signals overlap with display noise frequencies, then sensing performance deteriorates, but frequency allocation complexity increases

Engineering Contradiction:

Improvesensing performanceVSAvoidfrequency allocation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning specific frequency characteristics to individual transmission electrodes based on their spatial positions and local noise environments. Each electrode receives a frequency tailored to its specific location, avoiding local noise interference while maintaining overall system simplicity through localized optimization

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent systematically changes frequency parameters to ensure transmission signals do not overlap with display noise frequencies. By establishing clear frequency separation rules and allocating frequencies methodically, the system avoids noise interference while managing frequency allocation complexity through structured parameter selection

Inventive Principle:

Principle #35Parameter changes

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 enhances sensing performance and reduces power consumption by optimizing signal transmission and minimizing interference, thereby stabilizing input detection across larger display sizes.

Implementation Method 1

the sensor controller provides a plurality of transmission signals having different frequencies based on different lengths of the plurality of transmission wires to the plurality of transmission electrodes, respectively

Methodology Applied

Scientific EffectFrequency-division multiplexing:

Implementation Method 2

a plurality of reception electrodes that form mutual capacitors with the plurality of transmission electrodes, respectively

Methodology Applied

Scientific EffectMutual capacitance: Capacitance

Data Source

PatentUS12524109B2Display device with frequency-division multiplexing

Publication Date: 2026.01.13 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display panel, an input sensor, and a sensor controller. The input sensor includes transmission electrodes, reception electrodes, transmission wires electrically connecting the transmission electrodes to the sensor controller, and reception wires electrically connecting the reception electrodes to the sensor controller. The sensor controller provides transmission signals having different frequencies according to lengths of the transmission wires to the transmission electrodes, respectively. A frequency of each of the transmission signals does not overlap with a frequency component of display noise generated at a position of the display panel corresponding to each of the transmission electrodes, respectively.