Touch Sensor Segmentation for Self-Capacitance Resolution

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Solution Overview

Problem

Touch sensors face challenges in achieving high sensing resolution and alleviating retransmission issues, particularly in self-capacitance driving modes, where the detection of touch positions is less accurate and prone to noise due to electric field retransmission in low ground mass environments.

Innovation Solution

The touch sensor design includes specific arrangements of first and second sensing cells coupled to different electrical nodes, with the first sensing cells at borders of sensing blocks connected to different nodes, and second sensing cells extending in specific directions, allowing for improved detection of touch inputs and reducing retransmission issues by distributing the electric field effectively across multiple nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If self-capacitance driving mode is used to simplify the touch sensor structure, then device complexity is reduced, but measurement precision deteriorates due to lower touch detection accuracy and higher noise from electric field retransmission

Engineering Contradiction:

Improvetouch sensor structureVSAvoidtouch detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The touch sensor divides the sensing area into multiple sensing blocks, each containing first sensing cells coupled to a first electrical node and second sensing cells coupled to a second electrical node. This segmentation allows independent measurement of touch signals at different nodes, enabling the system to distinguish between genuine touch inputs and retransmitted electric field noise, thereby maintaining measurement precision while using the simpler self-capacitance driving mode.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If first sensing cells at borders of sensing blocks are coupled to the same electrical node to simplify wiring, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish retransmitted signals from actual touch inputs

Engineering Contradiction:

Improveelectrical node configurationVSAvoidtouch position determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent couples first sensing cells at borders of adjacent sensing blocks to different electrical nodes (first node and second node respectively). This segmentation creates independent measurement channels that can detect and differentiate retransmitted electric field signals from actual touch inputs, preventing false touch detections and improving position determination accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses the differential measurement between first and second electrical nodes to detect retransmitted signals. By comparing the touch signals measured at different nodes, the system can identify retransmitted electric field patterns and compensate for them, effectively eliminating their harmful impact on measurement precision.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If sensing cells are densely arranged to improve sensing resolution, then measurement precision is improved, but object-generated harmful factors worsen due to increased electric field retransmission and noise in low ground mass environments

Engineering Contradiction:

Improvesensing resolutionVSAvoidelectric field retransmission noise

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the densely arranged sensing cells into groups associated with different electrical nodes. This segmentation allows the system to measure and identify retransmitted noise patterns even at high density arrangements, enabling the distinction between genuine touch signals and retransmitted electric field interference, thereby maintaining sensing resolution while reducing the impact of harmful factors.

Inventive Principle:

Principle #1Segmentation

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 design enhances touch resolution in self-capacitance driving mode to match mutual capacitance driving mode accuracy, while significantly reducing retransmission issues, providing more precise touch detection and position determination.

Implementation Method 1

Each of the sensing blocks includes first sensing cells of a first group, first sensing cells of a second group, and second sensing cells

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11340723B2Touch sensor

Publication Date: 2022.05.24 SAMSUNG DISPLAY CO LTD

AI summary

A touch sensor includes sensing blocks. Each of the sensing blocks includes first sensing cells of a first group, first sensing cells of a second group, and second sensing cells. The first sensing cells of the first group are arranged in a first direction, spaced apart from each other with first separation areas therebetween, and coupled to an identical first electrical node. The first sensing cells of the second group are arranged in the first direction, spaced apart from each other with second separation areas therebetween, and coupled to an identical second electrical node. The second sensing cells respectively extend in a second direction in the first separation areas and the second separation areas. First sensing cells at borders of respective sensing blocks adjacent in the first direction are coupled to different electrical nodes.