Light to Heat Conversion Layer for OLED Transfer Accuracy

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Solution Overview

Problem

The existing light to heat conversion layers (LTHC layers) used in organic electroluminescence devices have insufficient visible light transmission properties, making it difficult to detect defects and achieve high transfer accuracy when using near-infrared absorbing materials like composite tungsten oxide fine particles.

Innovation Solution

A LTHC layer with visible light transmission properties is developed, utilizing composite tungsten oxide fine particles with a XRD peak top intensity ratio of 0.13 or more, which enhances near-infrared absorption and reduces haze, allowing for high positional accuracy in heat generation and improved transfer accuracy of organic electroluminescence devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional light absorbing materials (carbon black, metals, metal oxides, dyes) are used in the LTHC layer, then near-infrared absorption capability is improved, but visible light transmission property deteriorates (layer becomes very dark black with substantially no light transmission)

Engineering Contradiction:
Improvenear-infrared absorption capabilityVSAvoidvisible light transmission property
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent changes the physical and chemical parameters of the light absorbing material by using composite tungsten oxide fine particles with specific crystal structure (hexagonal W6O19 phase) and controlled particle size (1-100 nm). This parameter optimization enables the material to absorb near-infrared light effectively while maintaining visible light transmission, resolving the contradiction between near-infrared absorption and visible light transparency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite tungsten oxide fine particles as the light absorbing material, which combines multiple oxide phases (WO3, W6O19, and other tungsten oxides) in a specific ratio. This composite structure provides both strong near-infrared absorption capability and sufficient visible light transmission, overcoming the limitation of conventional single-material approaches that either absorb too much visible light or insufficient near-infrared light

Inventive Principle:
Principle #40Composite materials

2Power

If the LTHC layer uses materials with strong near-infrared absorption, then heat generation capability is improved, but defect detection capability deteriorates (cannot detect defects by visual observation or visible light sensor)

Engineering Contradiction:
Improveheat generation capabilityVSAvoiddefect detection capability
Core Design Contradiction:
PowerVSDifficulty of detecting and measuring

Solution Approach 1:

By optimizing the particle size of tungsten oxide fine particles to 1-100 nm and controlling the crystal phase composition, the patent achieves a balance where the layer generates sufficient heat for accurate transfer while remaining transparent enough to visible light for defect detection, resolving the contradiction between heat generation and defect detectability

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the LTHC layer achieves high near-infrared absorption, then transfer accuracy of organic electroluminescence devices is improved, but haze increases (reducing light transmission quality)

Engineering Contradiction:
Improvetransfer accuracyVSAvoidhaze
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent controls the particle size of tungsten oxide fine particles within 1-100 nm and optimizes the crystal phase composition to achieve low haze while maintaining high near-infrared absorption. This parameter control ensures that the LTHC layer produces concentrated heat at the irradiated site for accurate transfer without scattering visible light excessively, thus maintaining good light transmission quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent shifts the absorption特性 to the near-infrared dimension while maintaining visibility in the visible dimension. By targeting near-infrared light for absorption and heat generation, the layer achieves high transfer accuracy without compromising visible light transmission, effectively operating in different spectral dimensions to resolve the contradiction

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

The LTHC layer achieves low haze and high visible light transparency, enabling accurate heat generation only at the irradiated site, thereby improving the transfer accuracy of organic electroluminescence devices and allowing for defect detection, suitable for various applications including electronics and medicine.

Implementation Method 1

a layer including a light absorbing layer called a LTHC layer... when a specified site of the LTHC layer is irradiated with a laser beam, the light is absorbed by the LTHC layer to generate heat

Methodology Applied
Scientific EffectNear-infrared absorption: Absorption (EM radiation)

Implementation Method 2

the light is absorbed by the LTHC layer to generate heat which can transfer the organic electroluminescence device formed as a transferred layer

Methodology Applied
Scientific EffectPhotothermal conversion: Absorption (EM radiation)

Data Source

PatentEP3644099B1Light to heat conversion layer, method for producing same, and donor sheet using said light to heat conversion layer
Publication Date: 2024.02.21 SUMITOMO METAL MINING CO LTD
  • EP3644099B1 patent drawingFigure 1~2

AI summary

Provided are: a light to heat conversion layer which has visible light permeability, excellent near infrared absorption characteristics, and which can improve the transfer accuracy of an organic electroluminescent element using laser irradiation; and a donor sheet using said light to heat conversion layer. The light to heat conversion layer contains near infrared absorption particles and a binder component. The near infrared absorption particles are composite tungsten oxide microparticles wherein if the value for the XRD peak intensity of the (220) face of a silicon powder standard sample (manufactured by NIST, 640c) is defined as 1, the value for the ratio of XRD peak top intensity is at least 0.13, and the light transmissivity is at least 45%.