Touch Sensor Controller for Display Noise Compensation

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Solution Overview

Problem

Existing touch screen technologies face challenges in distinguishing between touch inputs and display noise, particularly in ultra-thin panels where parasitic capacitance increases, leading to reduced touch sensing sensitivity and accuracy.

Innovation Solution

A touch sensor controller is developed that includes a driving circuit for providing driving signals, a read-out circuit for generating touch and display noise data, and a processor to determine touch inputs by compensating for display noise, using techniques such as simultaneous display noise sensing and touch sensing, and applying positive and negative driving signals to differentiate between touch and noise signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the touch sensor is stacked on the display panel to reduce overall thickness, then the device becomes more compact and integrated, but parasitic capacitance increases leading to reduced touch sensing sensitivity

Engineering Contradiction:

Improveoverall thicknessVSAvoidtouch sensing sensitivity

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the sensing function by separating touch sensing and display noise sensing into different time periods. The touch sensor controller performs display noise sensing during a first period when no touch driving signal is applied, and touch sensing during a second period when the touch driving signal is applied. This temporal segmentation allows the system to maintain high touch sensing sensitivity despite the stacked configuration by compensating for display noise independently.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If display noise sensing is performed continuously to improve touch detection accuracy, then noise compensation is enhanced, but power consumption increases

Engineering Contradiction:

Improvetouch detection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by performing display noise sensing only during specific first periods when no touch driving signal is applied, rather than continuously. The controller alternates between display noise sensing periods and touch sensing periods. This periodic approach maintains accurate noise compensation while significantly reducing power consumption compared to continuous noise sensing.

Inventive Principle:

Principle #19Periodic action

3Speed

If touch sensing is performed during the entire display period to improve response time, then touch responsiveness is enhanced, but display noise interferes with touch signal accuracy

Engineering Contradiction:

Improvetouch response timeVSAvoidtouch signal accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing display noise sensing during first periods before touch sensing is performed. The controller measures and stores display noise characteristics in advance, then uses this pre-acquired noise data to compensate for touch signals during subsequent second periods. This preliminary noise measurement enables accurate touch detection without interference from real-time display noise.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a dedicated display noise sensing channel that operates independently from the touch sensing channel. The controller measures display noise through this separate channel during first periods, then uses the measured noise data as a compensation reference for processing touch signals during second periods. This intermediary noise measurement mechanism effectively separates and compensates for display noise interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11656729B2Touch sensor controller, operating method of touch sensor controller, and touch screen driving circuit

Publication Date: 2023.05.23 SAMSUNG ELECTRONICS CO LTD

AI summary

A touch sensor controller for driving a touch sensor that is stacked on a display panel and includes driving electrodes and receiving electrodes crossing the driving electrodes, the touch sensor controller including: a driving circuit configured to sequentially provide driving signals to the driving electrodes; a read-out circuit configured to, in response to the driving signals, generate touch data based on first sensing signals received from the receiving electrodes and generate display noise data based on a second sensing signal received from a first driving electrode to which a driving signal of the driving signals is not applied from among the driving electrodes; and a touch processor configured to determine whether a touch input has occurred on the touch sensor based on the touch data and the display noise data.