Rollable Touch Screen Panel Noise Compensation

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Solution Overview

Problem

Existing display devices with touch screen panels face challenges in maintaining touch sensing accuracy and noise reduction when the panel is rolled or unfolded, due to variations in capacitance values caused by changes in shape and ambient temperature.

Innovation Solution

A touch screen panel design with a touch driving circuit that applies driving signals to driving electrodes and receiving electrodes, compensates for noise by summing mutual capacitance and self-capacitance signals, and calculates touch coordinates, while being mounted on rollers for flexibility and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the touch screen panel is rolled or unfolded to enable flexible display, then adaptability and portability are improved, but touch sensing accuracy deteriorates due to capacitance value variations

Engineering Contradiction:

Improveflexible display capabilityVSAvoidtouch sensing accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The touch driving circuit measures self-capacitance values of driving electrodes and uses these measurements to compensate for noise in mutual capacitance sensing. This feedback mechanism dynamically adjusts for shape changes and temperature variations, maintaining touch sensing accuracy across different panel configurations during rolling and unfolding operations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the operating parameters by measuring self-capacitance values at different states (rolled vs. unfolded) and using these parameter changes to compensate for noise. The touch driving circuit adjusts compensation values based on the current shape state, allowing accurate touch detection regardless of panel configuration

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the touch screen panel is rolled or unfolded, then flexible display capability is improved, but noise increases due to ambient temperature changes and shape variations

Engineering Contradiction:

Improveflexible display capabilityVSAvoidnoise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The touch driving circuit continuously monitors self-capacitance values and uses this feedback to identify and compensate for noise caused by shape changes and temperature variations. The system dynamically adjusts compensation parameters based on real-time measurements, reducing noise impact during rolling and unfolding operations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent converts the harmful effect of shape changes and temperature variations (which cause noise) into a useful measurement signal. By measuring self-capacitance changes that occur during rolling and unfolding, the system generates compensation data that actively reduces noise, transforming the problematic variations into a solution

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If self-capacitance compensation is implemented to maintain touch accuracy, then touch sensing precision is improved, but device complexity increases

Engineering Contradiction:

Improvetouch sensing accuracyVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The touch driving circuit performs multiple functions using the same hardware resources: it drives the touch panel, measures mutual capacitance for touch detection, measures self-capacitance for noise compensation, and processes compensation values. This multi-functionality achieves high touch sensing accuracy without adding separate dedicated circuits for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 compensates for noise and maintains accurate touch sensing across shape changes, ensuring reliable touch input detection and improved signal-to-noise ratio.

Implementation Method 1

receiving a first sensing signal for sensing mutual capacitance formed between sensing nodes where the plurality of driving electrodes intersect with the plurality of receiving electrodes

Methodology Applied

Scientific EffectMutual capacitance: Capacitance

Implementation Method 2

receiving a second sensing signal for sensing self-capacitance between the plurality of driving electrodes and a ground plane

Methodology Applied

Scientific EffectSelf-capacitance: Capacitance

Data Source

PatentUS11531427B2Display device including touch screen panel

Publication Date: 2022.12.20 SAMSUNG ELECTRONICS CO LTD

AI summary

A display device, including: a touch screen panel including a touch panel and a display panel stacked under the touch panel; a touch driving circuit; and one or more rollers on which at least a portion of the touch screen panel is rolled. The touch panel may include receiving electrodes extending in a first axis direction and arranged in parallel in a second axis direction perpendicular to the first axis direction and driving electrodes extending in the second axis direction and arranged in parallel in the first axis direction. The display panel may include gate lines and source lines intersecting with the gate lines. The touch driving circuit may be configured to apply driving signals to the driving electrodes. The touch screen panel rolled on the one or more rollers may be unfolded as the one or more rollers slide in the first axis direction.