Phosphorescent Transfer Sheet Heat Management

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Solution Overview

Problem

Conventional light-accumulating transfer sheets emit insufficient intensity and duration of light due to inadequate heat management and pigment heating mechanisms.

Innovation Solution

A method involving a supporting layer, adhesive layer, resin layer, infrared absorption layer with carbon black, microcapsule layer containing heat-meltable content, and a pigment dispersion layer with strontium aluminate, where the infrared absorption layer generates heat through photothermal conversion, melting the microcapsule content to sustain the light-accumulating pigment's emission over an extended period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a conventional transfer sheet with light-accumulating pigment is used, then the transfer sheet can provide visibility in dark places, but the light emission intensity and duration are insufficient

Engineering Contradiction:
Improvelight emission intensityVSAvoidlight emission duration
Core Design Contradiction:
Illumination intensityVSDuration of action of moving object

Solution Approach 1:

The patent changes the physical state parameters of the pigment particles by enclosing them in microcapsules containing heat-meltable content. When heated, the microcapsule content melts and heats the pigment particles, changing their temperature and thereby improving both light emission intensity and duration. This parameter change approach transforms the pigment from a passive light-accumulating material to an actively heated light-emitting material.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition of the heat-meltable content within microcapsules. The content transitions from solid to liquid state when heated by infrared absorption, and this phase change process releases heat that sustains the pigment's light emission. The reversible solid-liquid transition enables prolonged heat supply to the pigment particles, extending the light emission duration.

Inventive Principle:
Principle #36Phase transitions

2Illumination intensity

If the infrared absorption layer is added to generate heat, then the light emission intensity and duration are improved, but the heat management becomes complex and requires microcapsule encapsulation

Engineering Contradiction:
Improvelight emission intensityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies nesting by placing pigment particles inside microcapsules, which are then embedded in the transfer sheet structure. The microcapsules contain heat-meltable content that surrounds and protects the pigment particles. This nested structure allows complex functionality (heat generation, heat storage, heat transfer) to be integrated within a compact multi-layered architecture without requiring external heating mechanisms.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The microcapsules act as intermediaries between the infrared absorption layer and the pigment particles. They receive heat from the infrared absorption layer, store it in their heat-meltable content, and then transfer it to the pigment particles. This intermediary structure manages the heat flow and protects the pigment particles while enabling improved light emission without direct contact between the infrared layer and pigment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If the microcapsule layer with heat-meltable content is added, then the heat retention and light emission duration are enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvelight emission durationVSAvoidmanufacturing ease
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-encapsulating the pigment particles in microcapsules containing heat-meltable content before incorporating them into the transfer sheet. This pre-preparation of functional units (microcapsules) allows for standardized manufacturing processes and simplifies the overall production, as the heat-retention functionality is already built into the pigment carrier units rather than requiring complex post-assembly steps.

Inventive Principle:
Principle #10Preliminary action

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 method enhances light emission intensity and duration, allowing the light-accumulating transfer sheet to emit high-luminance light for an extended period while maintaining heat within microcapsules, preventing leakage and ensuring repeated use without aging degradation.

Implementation Method 1

an infrared absorption layer comprising an infrared absorbent formed on the resin layer

Methodology Applied
Scientific EffectPhotothermal conversion: Photoacoustic Effect

Implementation Method 2

the microcapsules comprise a heat-meltable content which is reversibly solidified and melted by heat from the infrared absorption layer

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

a pigment dispersion layer containing a light-accumulating pigment formed on the microcapsule layer

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP3613607B1Phosphorescent transfer sheet, and transfer method of phosphorescent transfer sheet for inkjet
Publication Date: 2021.04.21 SANTOSHOJI
  • EP3613607B1 patent drawingFigure 1~4
  • EP3613607B1 patent drawingFigure 5~7
  • EP3613607B1 patent drawingFigure 8~9

AI summary

A method for producing a light-accumulating transfer sheet, comprising an adhesive layer forming step for forming an adhesive layer on a supporting layer; a resin layer forming step for forming a resin layer on the adhesive layer; an infrared absorbing layer forming step for forming an infrared absorbing layer comprising an infrared absorbent on the resin layer; a microcapsule layer forming step for forming a microcapsule layer, in which microcapsules are dispersed, on the infrared absorption layer; and a pigment dispersion layer forming step for forming a pigment dispersion layer containing a light-accumulating pigment on the microcapsule layer, wherein the microcapsules comprise a heat-meltable content which is reversibly solidified and melted by heat from the infrared absorption layer and an encapsulant for encapsulating the heat-meltable content.