Capacitive Touch Overlay With Interleaved Sensors

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Solution Overview

Problem

Current touch-sensitive displays in portable electronic devices face challenges in maintaining accuracy and resolution due to their decreasing size, requiring improvements in capacitive coupling and tactile feedback mechanisms to enhance user interaction.

Innovation Solution

The implementation of a capacitive touch-sensitive overlay with interleaved touch sensors, where each region includes two touch sensors with varying finger widths and gaps, providing increased capacitive coupling area detection and allowing for precise determination of touch coordinates without the need for jumpers or bridges, thereby reducing the number of layers and conductors, improving optical performance and manufacturing reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the size of portable electronic devices is decreased to improve portability, then portability is improved, but touch detection accuracy and resolution deteriorate

Engineering Contradiction:
Improvedevice sizeVSAvoidtouch detection accuracy
Core Design Contradiction:
Weight of moving objectVSMeasurement precision

Solution Approach 1:

The touch sensor is divided into multiple independent finger electrodes arranged in an interleaved pattern. Each finger electrode independently detects capacitive changes, and their collective signals provide precise touch location information even in compact device sizes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional single-layer or simple multi-layer trace arrangements to a three-dimensional interleaved structure where finger electrodes from different layers interlace. This vertical stacking with horizontal interleaving creates a dense detection network that maintains high resolution in reduced device footprints.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If traditional touch sensor layouts with jumpers and bridges are used, then manufacturing is simplified, but the number of layers and conductors increases, deteriorating optical performance and reliability

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidnumber of layers and conductors
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent removes the unnecessary jumper and bridge elements from traditional touch sensor designs. The interleaved finger electrode configuration provides complete electrical connectivity and signal routing directly through the sensor structure itself, eliminating redundant conductive paths and reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of multiple separate components (electrodes, conductors, and structural elements) into a unified interleaved finger electrode structure. This integration reduces the total number of discrete layers and conductors while maintaining all necessary electrical connections and mechanical support functions.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If non-interleaved trace patterns are used, then manufacturing is easier, but capacitive coupling area is reduced, deteriorating touch sensitivity

Engineering Contradiction:
Improvetrace pattern fabricationVSAvoidcapacitive coupling area
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent adds a vertical dimension to the trace pattern by stacking multiple layers of finger electrodes in an interleaved configuration. This three-dimensional arrangement dramatically increases the total capacitive coupling area between adjacent electrodes without increasing the planar footprint, thereby enhancing touch sensitivity while maintaining manufacturability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution enhances the accuracy and resolution of touch-sensitive displays by effectively determining touch coordinates through signal ratios from interleaved touch sensors, providing improved user interaction and reducing electrostatic discharge susceptibility, while maintaining a compact design.

Implementation Method 1

capacitive touch-sensitive overlay... providing increased capacitive coupling area detection... determined based on a ratio of signals from the first and second touch sensors

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2357549B1Capacitive touch sensitive overlay including touch sensor and electronic device including same
Publication Date: 2014.07.23 BLACKBERRY LTD
  • EP2357549B1 patent drawingFigure 1
  • EP2357549B1 patent drawingFigure 2~3
  • EP2357549B1 patent drawingFigure 4

AI summary

A touch-sensitive overlay includes a substrate, and a capacitive touch sensor arrangement comprising a first touch sensor and a second touch sensor disposed on the substrate in a region and arranged and constructed such that a coordinate of the touch is determined based on a relation of signals from at least the first and the second touch sensors, wherein the first touch sensor is electrically isolated from the second touch sensor.