Metal Microscopic Structure for Low-Concentration Analyte Detection

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Solution Overview

Problem

Existing metal microscopic structures for virus detection, such as those using surface-enhanced Raman spectroscopy or fluorescence, struggle to detect low-concentration analytes due to structural limitations.

Innovation Solution

A metal microscopic structure featuring a base member with protrusions covered by a metal film, where the film thickness in the gap between projections is greater than the protrusion height, ranging from 90% to 100% of the film thickness on top projections, enhancing surface plasmons and optical electric-field enhancement for improved sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional metal microscopic structures are used, then manufacturing is simpler, but detection sensitivity for low-concentration analytes is insufficient

Engineering Contradiction:

Improvedetection sensitivityVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The metal film thickness is varied locally across different regions: thicker in gap bottom portions (greater than protrusion height) and thinner on top portions (90-100% of gap bottom thickness). This local variation optimizes surface plasmon generation in gap regions while maintaining structural integrity, thereby improving detection sensitivity without excessive complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention transitions from conventional uniform 2D metal films to a 3D structured metal film with varying thickness across different spatial dimensions. The film thickness is optimized independently in vertical (z-axis) and horizontal (x-y plane) dimensions, creating a multi-dimensional structure that enhances detection capability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If uniform metal film thickness is used, then manufacturing is easier, but surface plasmon generation efficiency is reduced

Engineering Contradiction:

Improvesurface plasmon generation efficiencyVSAvoidfilm thickness uniformity

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The metal film is designed with locally differentiated thickness: the gap bottom portions have greater thickness (exceeding protrusion height) to maximize surface plasmon generation, while top portions have reduced thickness (90-100% of gap bottom thickness). This local quality variation optimizes optical performance without requiring extreme precision across the entire structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The film thickness parameter is changed from a uniform value to a spatially varying parameter. By controlling thickness to be greater than protrusion height in gaps and 90-100% of that thickness on tops, the structure optimizes electromagnetic field enhancement while maintaining manufacturability through controlled parameter variation

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If metal film thickness in gaps is increased, then detection sensitivity improves, but material usage and manufacturing complexity increase

Engineering Contradiction:

Improvedetection sensitivityVSAvoidmetal film quantity

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The metal film thickness is increased only where needed (in gap bottom portions) rather than uniformly across the entire structure. This localized thickening concentrates material in regions that contribute most to surface plasmon generation, improving detection sensitivity while minimizing overall metal consumption

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The film thickness in gap regions is made excessive (greater than protrusion height) to ensure sufficient surface plasmon generation, while thickness on top portions is kept partial (90-100% of gap bottom thickness). This partial/excessive approach optimizes performance in critical regions without proportionally increasing total material usage

Inventive Principle:

Principle #16Partial or excessive 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

This configuration allows for the detection of low-concentration analytes with high sensitivity by increasing the region for surface plasmon generation and stability, effectively holding more bound bodies, thereby enhancing detection accuracy.

Implementation Method 1

multiple projections made of a metal film covering the base member and configured to generate surface plasmons upon irradiation with light

Methodology Applied

Scientific EffectSurface plasmon generation: Surface Acoustic Wave

Data Source

PatentUS11567069B2Metal microscopic structure and detection device

Publication Date: 2023.01.31 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

One non-limiting and exemplary embodiment provides a metal microscopic structure capable of detecting a low-concentration analyte with high sensitivity. The metal microscopic structure includes a base member including multiple protrusions arrayed at predetermined intervals, and multiple projections made of a metal film covering the base member and configured to generate surface plasmons upon irradiation with light. A film thickness of the metal film positioned in a bottom portion of a gap between every adjacent two of the multiple projections is greater than a height of the multiple protrusions and is more than or equal to 90% and less than or equal to 100% of a film thickness of the metal film deposited on top portions of the multiple protrusions.