Self-Transformable Actuator for Rollable Displays Without External Machinery

Solution Overview

Problem

Existing flexible displays, such as OLEDs, require external machinery to roll or unfold, resulting in large and heavy devices due to the lack of self-transformability.

Innovation Solution

A self-transformable actuator using a first member made of an elastic body and a second member made of shape memory alloy, with a stopper and trigger, allowing bidirectional transformation between rolled and unrolled states through stored restoring forces and controlled power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If external mechanical assistance is used to roll or unfold the flexible display, then the display can be transformed between rolled and unrolled states, but the device becomes large and heavy due to complex machinery

Engineering Contradiction:

Improveself-transformation capabilityVSAvoiddevice weight

Core Design Contradiction:

Ease of operationVSWeight of moving object

Solution Approach 1:

The flexible display is equipped with actuators that enable it to roll and unroll automatically without external mechanical assistance. The actuator includes a first member with elastic properties that stores restoring force, and a second member made of shape memory alloy that changes shape in response to electrical signals, allowing the display to transform itself

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex external mechanical rolling machinery with an integrated actuator system that combines elastic materials and shape memory alloys. This substitution eliminates the need for heavy external mechanical devices while achieving the same rolling function through material properties and electrical actuation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If external mechanical assistance is used to roll or unfold the flexible display, then the display can be transformed between rolled and unrolled states, but the device becomes large and heavy due to complex machinery

Engineering Contradiction:

Improveself-transformation capabilityVSAvoiddevice volume

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The flexible display is equipped with actuators that enable it to roll and unroll automatically without external mechanical assistance. The actuator includes a first member with elastic properties that stores restoring force, and a second member made of shape memory alloy that changes shape in response to electrical signals, allowing the display to transform itself

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

When the flexible display is rolled, the entire display structure nests into a compact cylindrical form. The actuator components are integrated within the display structure, allowing the rolled display to be stored in a small volume while maintaining full functionality when unrolled

Inventive Principle:

Principle #7Nested doll (Nesting)

3Device complexity

If the flexible display is made self-transformable using elastic bodies and shape memory alloys, then external machinery is eliminated, but the actuator structure becomes more complex

Engineering Contradiction:

Improvemechanical structure complexityVSAvoidself-transformation capability

Core Design Contradiction:

Device complexityVSExtent of automation

Solution Approach 1:

The actuator is constructed by bonding a first member made of elastic body material and a second member made of shape memory alloy material. This composite structure combines the restoring force capability of elastic materials with the shape-changing capability of shape memory alloys to achieve bidirectional self-transformation

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The actuator structure serves multiple functions: the first member provides elastic restoring force for rolling motion, the second member provides shape memory effect for unrolling motion, and together they enable bidirectional transformation without requiring separate mechanical systems for each direction

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 flexible displays to roll or unfold without external machinery, reducing device weight and volume by utilizing shape memory alloys for bidirectional transformation.

Implementation Method 1

a first member (11) having a shape which is transformed from a first position which is any one of a rolled state or an unrolled state to a second position different from the first position and storing restoring force when the shape is transformed from the first position to the second position;

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a second member (13) bonded to the first member (11) in a longitudinal direction of the first member (11), and storing the shape of the second position

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Data Source

PatentUS12607171B2Self-transformable actuator and display device using same

Publication Date: 2026.04.21 LG ELECTRONICS INC

AI summary

An actuator according to one aspect of the present invention includes a first member in which a shape is transformed from a first position, which is either rolled or flat, to a second position different from the first position, and a restoring force is stored when the shape is transformed from the first position to the second position, and a second member which is joined to the first member along the length direction of the first member and in which the shape of the second position is stored.