Flexible Display Actuation Layer for Dynamic Haptic Surface Deformation

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Solution Overview

Problem

Current flexible display technologies for mobile devices lack the ability to dynamically change surface texture and provide haptic feedback, limiting user interaction and immersion, especially in curved or deformed configurations.

Innovation Solution

A flexible display structure comprising a deformable surface and an actuation structure with individually addressable electrically conductive actuators and a biasing layer, which can deform and return to their initial state, allowing for controlled surface deformation and haptic feedback without complex electronic components, using shape memory alloys or polymers and geometrically tortuous arms for efficient heating and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible display technologies are used to enable displays to bend or fold, then the display can be configured in curved or folded forms, but the display surface remains generally planar and uniform, limiting haptic feedback capability

Engineering Contradiction:
Improvedisplay configuration flexibilityVSAvoidhaptic feedback capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The display structure incorporates dynamically deformable surface portions that can change from a first configuration to a second configuration. Shape memory alloy actuators enable the display surface to transition between flat and curved states, providing dynamic haptic feedback while maintaining the flexible display's adaptability. This resolves the contradiction by making the surface properties changeable rather than static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameters of the display surface by introducing shape memory alloy actuators that alter the surface curvature and texture. These actuators enable the display to transition between different surface configurations (flat, curved, textured), providing haptic feedback capability without compromising the flexible display's fundamental adaptability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If complex electronic components are used to provide haptic feedback on flexible displays, then haptic feedback capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidelectronic components complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention replaces complex electronic haptic feedback components with a mechanical system based on shape memory alloy actuators. These actuators use thermomechanical properties of smart materials to produce haptic feedback effects, eliminating the need for complex motors, sensors, and control electronics while maintaining haptic feedback capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The display structure utilizes parameter changes in shape memory alloy materials (phase transitions between austenite and martensite) to generate haptic feedback. This material-based approach simplifies the overall system by replacing electronic control mechanisms with intrinsic material properties, reducing device complexity and cost.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If shape memory alloy actuators are used for surface deformation, then haptic feedback is enabled, but heating of the actuators is required which increases power consumption

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The shape memory alloy actuators are activated periodically or intermittently rather than continuously, only when haptic feedback is required. This periodic activation reduces overall power consumption compared to continuous operation, while still providing effective haptic feedback capability when needed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention exploits phase transitions in shape memory alloys (between austenite and martensite phases) to generate haptic feedback. By utilizing these phase transitions, the system achieves efficient actuation with lower energy requirements compared to traditional electromagnetic actuators, as the phase change process itself generates the mechanical work needed for haptic feedback.

Inventive Principle:
Principle #36Phase transitions

4Ease of operation

If the display surface is made deformable to provide haptic feedback, then user interaction is improved, but the display structure thickness increases

Engineering Contradiction:
Improveuser interaction capabilityVSAvoiddisplay structure thickness
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The invention uses thin-film shape memory alloy actuators integrated into the flexible display structure. These thin-film actuators provide the necessary surface deformation for haptic feedback while maintaining the overall thin profile of the display, avoiding significant thickness increases.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The haptic feedback mechanism is implemented through out-of-plane surface deformations rather than increasing the in-plane dimensions or overall thickness. The shape memory alloy actuators create localized surface curvature changes that provide haptic feedback without adding significant thickness to the display structure.

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

Enables a thin, low-cost, and versatile display solution that supports touch inputs and haptic feedback, allowing for varied deformations and improved user interaction, such as mimicking keyboard keys or providing immersive experiences, while maintaining a thin form factor and low power consumption.

Implementation Method 1

the actuators are configured to deform upon application of an electrical current and/or thermal energy. In an example, application of an electrical signal causes resistive heating in an arm, thus increasing the temperature of the material from which the arm is formed thereby provoking a deformation by way of, e.g., contraction of the material

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

each of the resiliently biased portions configured to urge the corresponding actuator of the actuation layer in a second direction opposite to the first direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

application of an electrical signal causes resistive heating in an arm, thus increasing the temperature of the material from which the arm is formed thereby provoking a deformation

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP4127885B1Flexible display structures for user equipment
Publication Date: 2024.06.26 HUAWEI TECH CO LTD
  • EP4127885B1 patent drawingFigure 1
  • EP4127885B1 patent drawingFigure 2
  • EP4127885B1 patent drawingFigure 3~3(d)

AI summary

In some examples, a flexible display structure for user equipment, in which the display structure comprises a deformable display surface and an actuation structure configured to deform the deformable surface, comprises an actuation layer comprising multiple individually addressable electrically conductive actuators each of which being so positioned as to deform a selected portion of the display surface in a first direction, and a biasing layer comprising multiple resiliently biased portions, each one of which so positioned as to correspond with an actuator of the actuation layer, and so configured as to accompany deformation of the deformable surface at a selected portion, each of the resiliently biased portions configured to urge the corresponding actuator of the actuation layer in a second direction opposite to the first direction. The actuation layer is disposed between the deformable display surface and the biasing layer.