Plasmonic Color Printing via Dual-Resolution Lithography

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Solution Overview

Problem

Current methods for producing color images using metallic nanostructures by plasmonic resonance are costly and inefficient, especially for producing different color images or large image sizes, due to the reliance on expensive techniques like electron-beam lithography and limited control over nanostructure sizes and separations.

Innovation Solution

A method involving a substrate with a photosensitive layer exposed to high-resolution and low-resolution periodic patterns of dose distribution, allowing for the formation of metallic nanofeatures with spatial variations in lateral dimensions that correspond to color distributions in the desired image, using photolithographic techniques like interference or displacement Talbot lithography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If electron-beam lithography is used to form metallic nanostructures for color images, then manufacturing precision and control over nanostructure sizes are improved, but device complexity and production cost increase significantly

Engineering Contradiction:
Improvecontrol over nanostructure sizesVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention segments the lithographic process into two distinct stages: a first lithographic step that defines the periodic array structure, and a second lithographic step that defines the variable size/shape of individual nanostructures. This segmentation allows each step to be optimized independently, reducing overall process complexity while maintaining manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first lithographic step performs preliminary action by pre-defining the periodic array structure and positions before the second lithographic step modifies the nanostructure sizes. This preliminary structuring simplifies the second step, as it only needs to adjust sizes rather than define positions from scratch, thereby reducing device complexity.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If multiple colour dyes are deposited to achieve a range of colours, then colour variety is improved, but device complexity and material requirements increase

Engineering Contradiction:
Improvecolour varietyVSAvoidcartridge system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention changes the controlling parameter for color generation from material composition (multiple dyes) to geometric parameters (size, shape, and spacing of metallic nanostructures). By varying these geometric parameters, a wide range of colors can be achieved using a single material system, thereby reducing device complexity and eliminating the need for multiple dye cartridges.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If micrometre-sized ink spots are used in industrial printing methods, then ease of manufacture is improved, but measurement precision and image resolution deteriorate

Engineering Contradiction:
Improveprinting process simplicityVSAvoidimage resolution
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention extracts the color generation function from the ink material itself and relocates it to the geometric configuration of metallic nanostructures. This allows the use of larger, easier-to-manufacture ink spots while achieving high resolution through the sub-wavelength periodic structures that generate color via plasmonic resonance rather than through small dye molecules.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If serial research-grade methods are used to dispense dyes at higher resolution, then measurement precision is improved, but productivity decreases

Engineering Contradiction:
Improvedye dispensing resolutionVSAvoidproduction speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The invention employs periodic action through lithographic techniques that can simultaneously define thousands of nanostructures in a periodic array pattern across the entire image area in a single exposure step. This parallel periodic structuring achieves high resolution while maintaining high productivity, eliminating the serial bottleneck of research-grade dye dispensing methods.

Inventive Principle:
Principle #19Periodic 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

Enables cost-effective production of color images with high resolution and variability, reducing the need for expensive master masks and allowing for mass production of color images with improved efficiency and control over nanostructure dimensions.

Implementation Method 1

a) providing a substrate having a layer of photosensitive material; b) exposing the layer to a high-resolution periodic pattern of dose distribution

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

forming a pattern of metallic nanofeatures that generates by plasmonic resonance a desired image having a distribution of colours

Methodology Applied
Scientific EffectPlasmonic resonance: Resonance

Data Source

PatentEP3237973B1Method for printing colour images
Publication Date: 2019.08.21 EULITHA
  • EP3237973B1 patent drawingFigure 1
  • EP3237973B1 patent drawingFigure 2a~2c
  • EP3237973B1 patent drawingFigure 3~4

AI summary

A method for forming a pattern of metallic nanofeatures that generates by plasmonic resonance a desired image having a distribution of colours, which method includes providing a substrate having a layer of photosensitive material, exposing the layer to a high-resolution periodic pattern of dose distribution, determining at least one low-resolution pattern of dose distribution such that the sum of the at least one low-resolution pattern of dose distribution and the high-resolution periodic pattern of dose distribution is suitable for forming the pattern of metallic nanofeatures, wherein the lateral dimensions of said metallic nanofeatures have a spatial variation across the pattern that corresponds to the distribution of colours in the desired image, exposing the layer of photosensitive material to said at least one low-resolution pattern of dose distribution, developing the layer of photosensitive material to produce a pattern of nanostructures in the developed photosensitive material, processing the pattern of nanostructures so that the pattern of metallic nanofeatures is formed with said spatial variation of lateral dimension across the pattern that corresponds to the distribution of colours in the desired image.