Shape-Shifting Hood Layer for Thermal Warning in Lighters

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Solution Overview

Problem

Flame producing assemblies, such as lighters, often have hoods that absorb thermal energy from the flame, leading to temperatures above 60 °C, causing user discomfort or injury upon touch, especially when handheld or placed in clothing pockets.

Innovation Solution

Incorporating a shape-shifting layer made of nematic liquid crystal elastomer on the hood that changes shape above 40 °C, protruding outward when heated to alert users of unsafe temperatures, thereby reducing the risk of injury and protecting clothing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the hood is used to shield the flame and protect the user, then the protective function is improved, but the hood temperature rises above 60°C causing user discomfort or injury

Engineering Contradiction:
Improveprotective functionVSAvoidthermal injury risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a shape-shifting layer that undergoes visible shape changes in response to temperature variations. When the hood temperature exceeds the safe threshold (above 40°C), the shape-shifting layer transforms from a first shape to a second shape, providing visual and tactile indication to users that the surface is too hot to touch. This resolves the contradiction by maintaining the protective shielding function while adding a passive thermal warning system that prevents user injury without requiring active control mechanisms.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The shape-shifting layer acts as an intermediary between the hot hood surface and the user. It absorbs thermal energy and translates it into a shape transformation that serves as a warning signal. This intermediary layer allows the hood to maintain its protective function while preventing direct thermal contact between the user and the overheated surface, thus resolving the contradiction between protection and thermal safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the flame producing assembly is designed as a handheld device, then the ease of operation is improved, but the risk of accidental contact with hot surfaces increases

Engineering Contradiction:
ImproveportabilityVSAvoidaccidental touch injury
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The shape-shifting layer provides visual and tactile feedback that changes with temperature. When the handheld device is in use and the hood becomes hot, the layer transforms shape to alert users not to touch the surface. This resolves the contradiction by enabling portable handheld operation while incorporating a passive safety mechanism that prevents accidental thermal injury through intuitive shape-based warning signals.

Inventive Principle:
Principle #32Color changes

3Reliability

If the hood absorbs thermal energy to protect from flame, then the protective function is improved, but the hood reaches temperatures that can damage clothing

Engineering Contradiction:
Improveheat protectionVSAvoidclothing damage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The shape-shifting layer transforms shape when the hood temperature exceeds safe thresholds (above 40°C), providing visual and tactile indication that the surface temperature is high enough to potentially damage clothing. This allows the hood to maintain its heat protection function while warning users of temperatures that could harm surrounding materials like clothing pockets.

Inventive Principle:
Principle #32Color changes

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

The shape-shifting layer effectively indicates safe and unsafe temperatures through visible and tactile changes, preventing user contact with hot surfaces and protecting clothing from damage.

Implementation Method 1

a shape-shifting layer provided on the hood. The shape-shifting layer is configured to shape-shift from a first shape to a second shape when heated above a first threshold temperature

Methodology Applied
Scientific EffectShape-shifting: Shape Memory Polymer

Implementation Method 2

the shape-shifting layer is configured to shape-shift from a first shape to a second shape when heated above a first threshold temperature, wherein the first threshold temperature is at least about 40°C

Methodology Applied
Scientific EffectThermal response: Thermal Expansion

Implementation Method 3

the liquid crystal elastomer is in a liquid crystalline phase at a temperature below the second threshold temperature and in a random coil conformation above the first threshold temperature

Methodology Applied
Scientific EffectPhase transition: Phase Change

Data Source

PatentEP4528161A1Flame producing assembly comprising a shape-shifting layer
Publication Date: 2025.03.26 BIC VIOLEX SINGLE MEMBER SA
  • EP4528161A1 patent drawingFigure 1A~1B
  • EP4528161A1 patent drawingFigure 2A~2B
  • EP4528161A1 patent drawing

AI summary

The present disclosure relates to a flame producing assembly (10) comprising a hood (12) configured to shield a flame produced by the flame producing assembly (10) from wind and/or protect a user from heat generated by the flame; and a shape-shifting layer (14) provided on the hood (12). The shape-shifting layer (14) is configured to shape-shift from a first shape to a second shape when heated above a first threshold temperature, wherein the first threshold temperature is at least about 40°C.