Wedge-Shaped Self-Capacitance Electrodes for Multi-Touch Precision

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Solution Overview

Problem

Current multi-touch technologies using the self-capacitance principle face challenges in accurately determining touch positions with high sensitivity and precision, particularly in recognizing multiple touch points and active pen inputs, due to limitations in electrode design and signal interference.

Innovation Solution

The touch structure employs wedge-shaped self-capacitance electrodes arranged in a grid pattern with complementary shapes and sub-traces, allowing for precise signal detection and enhanced sensitivity by dividing each electrode into regions with varying capacitance, enabling accurate determination of touch positions and supporting multi-touch and active pen recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional electrode designs are used in self-capacitance multi-touch technology, then the manufacturing process is simpler, but the touch sensitivity and precision are insufficient for accurately determining multiple touch points and active pen inputs

Engineering Contradiction:
Improvetouch position determination accuracyVSAvoidelectrode structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each touch electrode is divided into multiple sub-electrodes arranged in matrix form, allowing the system to detect touch positions by measuring capacitance changes across multiple segmented regions. This segmentation enables precise multi-touch detection while maintaining a relatively simple overall electrode structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements different electrode configurations in different regions of the touch panel. Specifically, edge regions have electrodes extending to the boundaries while central regions have electrodes that do not reach edges, creating local variations in electrode quality that improve touch detection accuracy at different positions without requiring complete redesign of the entire electrode system.

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If edge-touch electrodes are extended to the display edges, then the frame width can be reduced, but signal interference and manufacturing complexity increase

Engineering Contradiction:
Improveframe widthVSAvoidmanufacturing complexity
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

Edge-touch electrodes are divided into multiple sub-electrodes that are independently controllable. This segmentation allows the system to manage signal interference from edge electrodes by selectively activating or deactivating specific sub-electrodes during different detection phases, reducing manufacturing complexity while maintaining narrow frame width.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of electrode activation states. Different subsets of sub-electrodes are activated in different time periods during the detection process, allowing the system to adaptively manage signal interference from edge electrodes while maintaining the reduced frame width design.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple subsets of electrodes are used for detection, then multi-touch accuracy improves, but the detection process becomes more complex

Engineering Contradiction:
Improvemulti-touch detection accuracyVSAvoiddetection process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection process uses periodic switching between different subsets of sub-electrodes. By systematically activating different electrode subsets in a periodic manner, the system can distinguish between multiple touch points through pattern recognition, improving multi-touch accuracy while managing detection complexity through structured periodic operations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system measures capacitance values from multiple sub-electrode subsets and uses this feedback information to determine touch positions. By analyzing the spatial distribution and magnitude of capacitance changes across different subsets, the system can accurately identify multiple touch points while the feedback mechanism organizes the complexity into a systematic detection algorithm.

Inventive Principle:
Principle #23Feedback

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 achieves higher touch sensitivity and precision, enabling accurate multi-touch detection and recognition of active pen inputs, while simplifying the manufacturing process and reducing frame width, thus improving the overall performance of touch devices.

Implementation Method 1

The capacitive touch technology may be divided into touch technology using the mutual-capacitance principle and touch technology using the self-capacitance principle

Methodology Applied
Scientific EffectSelf-capacitance: Capacitance

Data Source

PatentEP3767446B1Touch structure and manufacturing method therefor, touch device, and touch positioning method
Publication Date: 2024.02.21 BOE TECHNOLOGY GROUP CO LTD
  • EP3767446B1 patent drawingFigure 1A
  • EP3767446B1 patent drawingFigure 1B~1C
  • EP3767446B1 patent drawingFigure 1D~2A

AI summary

A touch structure, a method of manufacturing same, a touch device, and a method for determining a touch position are provided. The touch structure includes a first touch unit (1) and the first trace (13). The first touch unit (1) includes a first touch electrode (11) and a second touch electrode (12) that are adjacent to each other and insulated from each other. The first touch electrode (11) and the second touch electrode (12) are both self-capacitance electrodes and both have a thin end (11A, 12A) and a thick end (11B, 12B) that are arranged opposite to each other. The first trace (13) includes a first sub-trace (131) and a second sub-trace (132). The first sub-trace (131) is coupled to the first touch electrode (11) and the second sub-trace (132) is coupled to the second touch electrode (12). The touch structure is able to realize multi-point touch.