Core-Shell Upconverting Microparticles for Weak Near-Infrared Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional photoelectric conversion elements have low detection sensitivity for near-infrared light and require a more efficient and cost-effective method to convert near-infrared light into visible light for improved photoelectric conversion efficiency.

Innovation Solution

A core-shell type upconverting microparticle with a hexagonal columnar shape, specific diameter and thickness ratios, and a sol-gel method for manufacturing, utilizing doped rare earth atoms for energy conversion from near-infrared to visible light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If upconverting particles are manufactured by hydrothermal method, then upconverting light emission can be achieved, but manufacturing cost increases and process complexity increases due to high temperature and high pressure conditions

Engineering Contradiction:
Improveupconverting light emissionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the manufacturing parameters from high temperature and high pressure (hydrothermal method) to room temperature or mild heating conditions (sol-gel method). This parameter change maintains the upconverting light emission function while significantly reducing manufacturing cost and process complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/thermal system of hydrothermal synthesis with a chemical system based on sol-gel chemistry. The sol-gel method uses chemical reactions in solution to form the upconverting particle structure, eliminating the need for high temperature and pressure equipment

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

2Productivity

If upconverting particles are used for near-infrared conversion, then photoelectric conversion efficiency can be improved, but manufacturing complexity increases due to core-shell structure requirements

Engineering Contradiction:
Improvephotoelectric conversion efficiencyVSAvoidcore-shell structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the core and shell formation into a single sol-gel processing step, eliminating the need for separate synthesis and coating processes. The core-shell structure forms simultaneously during the sol-gel reaction, reducing manufacturing complexity while maintaining the functional benefits of the core-shell architecture

Inventive Principle:
Principle #5Merging (Combining)

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 upconverting light emission under low excitation light like sunlight, enhances sensitization characteristics for weak near-infrared light, and is manufactured at lower costs.

Implementation Method 1

the upconverting refers to a phenomenon in which low-energy light (long-wavelength light, for example infrared light) is converted into high-energy light (short-wavelength light, for example, visible light or ultraviolet light)

Methodology Applied
Scientific EffectUpconverting light emission: Photoluminescence

Implementation Method 2

long-wavelength light such as near-infrared light absorbed by inorganic core-shell particles is converted into short-wavelength light such as visible light

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP4692278A1Core-shell type upconverting microparticle, upconverting micro precursor particle, sensitizing core-shell type upconverting microparticle, tio2-coated core-shell type upconverting microparticle, near-infrared detector, photoelectric conversion element, and method for producing core-shell type upconverting microparticle
Publication Date: 2026.02.11 THE JAPAN SCI & TECH AGENCY
  • EP4692278A1 patent drawingFigure 1~2
  • EP4692278A1 patent drawingFigure 3~4
  • EP4692278A1 patent drawingFigure 5(a)~5(c)

AI summary

A core-shell type upconverting microparticle is an upconverting particle that includes: a core portion; and a shell portion that covers the core portion, the particle has a hexagonal columnar shape, a particle diameter of equal to or greater than 300 nm, and a thickness of equal to or greater than 100 nm, and an aspect ratio as the particle diameter/the thickness is equal to or greater than 1.2 and equal to or less than 5.0.