Surface Relief Microstructure Replication Without Masks

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Solution Overview

Problem

Current methods for producing replicas of surface relief microstructures are complex and time-consuming, leading to decreased manufacturing yield and increased production time, particularly due to the need for multiple process steps and the use of masks.

Innovation Solution

A method that eliminates the need for mask manufacturing by using a master with a surface relief microstructure to replicate the patterned surface relief microstructure through dry or wet etching processes, where the replica has an inverse surface relief profile, allowing for the use of standard replication techniques like UV embossing and hot embossing to mass-produce optical elements with reduced process steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional methods using masks are used to produce replicas of surface relief microstructures, then the replication process can be performed, but the number of process steps increases and production time increases

Engineering Contradiction:
Improvereplication accuracyVSAvoidnumber of process steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent removes the mask from the replication process entirely. Instead of using a mask to define the pattern, the method directly transfers the surface relief microstructure from the master to the replica material through contact replication, eliminating the mask manufacturing and alignment steps while maintaining replication accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The master with the surface relief microstructure is prepared in advance, containing all the pattern information needed for replication. This preliminary preparation of the master allows subsequent replicas to be produced directly without requiring masks, as the master itself serves as the pattern definition source

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If traditional methods using masks are used to produce replicas of surface relief microstructures, then the replication process can be performed, but production time increases

Engineering Contradiction:
Improvereplication accuracyVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

By removing the mask step from the process, the patent eliminates the time required for mask manufacturing, alignment, and removal. The direct contact replication method allows the pattern transfer to occur in a single step, significantly reducing production time while maintaining replication fidelity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The method creates direct physical copies of the surface relief microstructure from the master to the replica material through contact replication. This copying process eliminates intermediate steps involving masks, allowing rapid production of accurate replicas without the time penalty of mask-based methods

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If traditional methods using masks are used to produce replicas of surface relief microstructures, then the replication process can be performed, but manufacturing yield decreases

Engineering Contradiction:
Improvereplication accuracyVSAvoidmanufacturing yield
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By eliminating the mask step, the patent removes potential failure points associated with mask manufacturing defects, mask alignment errors, and mask damage during the process. This results in higher manufacturing yield as the direct contact replication method is more robust and less prone to errors

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The direct copying method from master to replica material ensures high fidelity replication without the intermediate mask step that could introduce defects. This approach improves manufacturing yield by reducing the number of opportunities for errors to occur during the replication process

Inventive Principle:
Principle #26Copying

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 approach simplifies the replication process, increases manufacturing yield, and allows for cost-effective mass production of optical elements with enhanced optical properties, such as light modulation, diffraction, and scattering, while reducing the number of process steps and production time.

Implementation Method 1

The copied surface relief microstructure is etched into the second material layer

Methodology Applied
Scientific EffectEtching:

Implementation Method 2

the light is diffracted, refracted or scattered

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

the light is diffracted, refracted or scattered

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

The use of isotropic and even more anisotropic scattering effects in OVDs can enhance the optical attractiveness significantly

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP2399151B1Surface relief microstructures, related devices and method of making them
Publication Date: 2019.11.27 ROLIC TECHNOLOGIES AG
  • EP2399151B1 patent drawingFigure 1.1~1.2
  • EP2399151B1 patent drawingFigure 2~4
  • EP2399151B1 patent drawingFigure 5~5.6

AI summary

The present invention relates to a method for the replication of a patterned surface relief microstructure, comprising the steps of generation of a first layer with a patterned surface relief microstructure, generation of a master, by copying the microstructure of the first layer into a second layer, thereby involving at least one dry or wet etching step, characterized by an additional step, in which the microstructure of the master is brought into contact with a replica material, such that the microstructure of the master is reproduced in the replica. The invention further relates to the elements made as a replica according to the method. The surface relief microstructures are suitable to display images with a positive- negative and/or color image flip. The elements according to the invention are particularly useful for securing documents and articles against counterfeiting and falsification.