Touchscreen Electrodes Switching Between Touch Sensing and Haptics

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Solution Overview

Problem

Integrating capacitive touchscreen and electrotactile technology in the same electronic display poses challenges, including capacitive cross-coupling that prevents touch input detection, accidental triggering of sensors, and potential damage to measurement circuits due to the electrotactile layer's interference with capacitive touch sensors.

Innovation Solution

Using the same electrodes for both touch input detection and haptic feedback, eliminating the need for a separate electrotactile layer, which reduces capacitive cross-coupling and simplifies the device structure, allowing the electrodes to switch between states for touch sensing and haptic feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a separate electrotactile layer is added to provide haptic feedback, then haptic functionality is improved, but capacitive cross-coupling occurs that prevents touch input detection

Engineering Contradiction:
Improvehaptic feedback functionalityVSAvoidtouch input detection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the electrotactile layer with the touchscreen electrode structure, making the touchscreen electrodes serve dual purposes: touch sensing and haptic feedback generation. This integration eliminates the need for a separate electrotactile layer and resolves the capacitive cross-coupling issue by unified control of the electrode system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touchscreen electrodes are designed to perform multiple functions: detecting touch inputs through capacitive sensing and providing haptic feedback through electrotactile effects. This multi-functionality is achieved by controlling the electrodes in different operational modes without requiring separate dedicated components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an electrotactile layer is integrated with capacitive touch sensors, then haptic feedback is enabled, but accidental triggering of sensors occurs

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidtouch sensor accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system dynamically switches between touch sensing mode and haptic feedback mode based on operational requirements. During touch detection, the electrodes are configured for high-precision capacitive sensing; during haptic output, the same electrodes are configured for electrotactile feedback, preventing accidental triggering.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic timing sequences where touch sensing operations and haptic feedback operations are separated in time. This periodic alternation allows the electrodes to be optimized for their respective functions during different time intervals, preventing interference and accidental triggering.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If an electrotactile layer is added to the touchscreen, then haptic feedback is provided, but the device structure becomes more complex

Engineering Contradiction:
Improvehaptic feedback functionalityVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The electrotactile layer is merged with the existing touchscreen electrode structure, eliminating the need for separate electrotactile components. This integration reduces device complexity by utilizing the touchscreen electrodes for both touch sensing and haptic feedback generation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touchscreen electrodes serve dual purposes as both touch sensors and haptic actuators, reducing the overall component count and structural complexity. This multi-functional design eliminates the need for separate electrotactile layers while maintaining both touch sensing and haptic feedback capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If an electrotactile layer is integrated with capacitive touch sensors, then haptic feedback is enabled, but manufacturing precision requirements increase

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidelectrode positioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The electrotactile functionality is merged into the existing touchscreen electrode manufacturing process, utilizing the same electrode patterns and positioning already established for touch sensing. This approach maintains existing manufacturing precision standards without requiring additional precision requirements.

Inventive Principle:
Principle #5Merging (Combining)

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 approach enables a more straightforward and cost-effective manufacturing process, improves durability by removing the need for additional layers, and allows for flexible touchscreen designs without compromising haptic feedback functionality.

Implementation Method 1

a capacitive touch sensor comprises an electrode and a measurement circuit, where the electrode is configured for use in the detection of a touch input by a user of the device

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

an electrotactile surface which takes advantage of capacitive coupling to the user's skin to create a variable frictional force on the touchscreen panel

Methodology Applied
Scientific EffectElectrotactile effect: Electrostatic Induction

Data Source

PatentEP2771772B1Touchscreen with haptic feedback
Publication Date: 2021.07.28 NOKIA TECHNOLOGIES OY
  • EP2771772B1 patent drawingFigure 1a~2b
  • EP2771772B1 patent drawingFigure 2c~3b
  • EP2771772B1 patent drawingFigure 3c~4b

AI summary

An apparatus comprising at least oneprocessor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to provide a first state or a second state for an electrode, wherein in the first state, the electrode is configured for use in the detection of touch input, and in the second state, the electrode is configured for use in the provision of haptic feedback.