Touch Controller Noise Detection Circuit for Display Panel Sensitivity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

As the distance between a display panel and a touch panel decreases, parasitic capacitance increases, leading to display noise that reduces touch sensing sensitivity in touch screen devices.

Innovation Solution

A touch controller is stacked on the display panel, equipped with a noise detection circuit to provide different reference voltages to sensing electrodes, a driving signal generation circuit to alternately select noise voltages, and a receiving circuit to generate a sensing voltage based on the touch sensing signal and driving signal, thereby reducing display noise and improving touch sensing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the distance between display panel and touch panel is decreased, then device thickness is reduced, but display noise increases and touch sensing sensitivity deteriorates

Engineering Contradiction:

Improvedevice thicknessVSAvoidtouch sensing sensitivity

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the touch sensor array into multiple groups (first group and second group) with different scanning timings. By alternately selecting and scanning these groups, the system reduces the impact of display noise on any single group, thereby maintaining touch sensing sensitivity even when the distance between display and touch panels is reduced.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic scanning of different electrode groups by alternately selecting first and second groups of sensing electrodes. This periodic action allows the system to capture noise characteristics at different time points and perform differential processing, effectively reducing display noise interference while maintaining close coupling between display and touch panels.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If different reference voltages are provided to different electrode groups, then display noise is reduced, but device complexity increases

Engineering Contradiction:

Improvenoise reduction capabilityVSAvoidcontrol circuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a single reference voltage generation unit that serves multiple electrode groups through time-division multiplexing. By alternately providing the same reference voltage to different groups at different times, the system achieves noise reduction through differential scanning without requiring separate reference voltage generators for each group, thus avoiding increased device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the temporal parameter (scanning time) rather than the voltage parameter (reference voltage level) to differentiate between electrode groups. By scanning different groups at different times with the same reference voltage, the system achieves noise reduction through time-division multiplexing without complicating the voltage generation circuitry.

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

The solution effectively reduces display noise interference, enhancing the sensitivity of touch sensing signals by compensating for parasitic capacitance-induced noise, thereby improving the accuracy of touch input detection.

Implementation Method 1

As a distance between a display panel and a touch panel decreases, parasitic capacitance between electrodes of the display panel and the touch panel may increase

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Implementation Method 2

a driving signal generation circuit configured to receive a first noise voltage and a second noise voltage generated based on the first reference voltage and the second reference voltage

Methodology Applied

Scientific EffectVoltage differentiation:

Implementation Method 3

a receiving circuit configured to receive the driving signal via a first input terminal, receive a touch sensing signal generated based on the driving signal via a second input terminal connected to a third electrode

Methodology Applied

Scientific EffectDifferential signal processing:

Data Source

PatentUS11960680B2Touch controller, operating method of the same, and touch sensing device including touch controller

Publication Date: 2024.04.16 SAMSUNG ELECTRONICS CO LTD

AI summary

A touch controller includes a noise detection circuit that respectively provides a first reference voltage and a second reference voltage for detecting display noise to a first electrode and a second electrode arranged on lines except a line on which touch sensing is performed, among sensing electrodes, the second reference voltage being different from the first reference voltage, a driving signal generation circuit that receive a first noise voltage and a second noise voltage generated based on the first reference voltage and the second reference voltage and alternately selects the first noise voltage and the second noise voltage as a driving signal, and a receiving circuit that receives the driving signal, a touch sensing signal generated based on the driving signal from a third electrode arranged on the line on which touch sensing is performed, among the sensing electrodes, and generates a sensing voltage based on the touch sensing signal.