Microlens Embossing on Arcuate Substrates via UV-Cured Resin

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Solution Overview

Problem

Existing methods for producing microlenses from plastics or resins result in significant misshaping due to the high viscosity of the melt, leading to incomplete filling of the form tool and resulting in optically distorted or incomplete reproductions of objects.

Innovation Solution

A procedure involving an arched substrate and a quick-running printing machine is used to produce microlenses through a stamping process, where a layer of plastic or resin is applied and shaped using a form tool with cavities of specific contours, and then hardened with UV radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If embossing process is used to form microlenses from plastic or resin melt, then microlenses can be produced on substrate, but the high viscosity of the melt causes incomplete filling of the mold and formation of protrusions on microlens edges

Engineering Contradiction:

Improveembossing processVSAvoidmicrolens shape accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies a release agent to the mold surface before applying the plastic or resin melt. This preliminary action prevents the viscous melt from adhering to the mold walls, allowing it to flow completely into the cavity and form accurate microlens shapes without protrusions, while still enabling easy demolding after curing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The release agent acts as an intermediary substance between the mold surface and the plastic/resin melt. This intermediary layer reduces adhesion and friction, facilitating complete mold filling despite the high viscosity of the melt, while allowing the cured microlenses to be released from the mold without damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If more plastic or resin melt is applied to ensure complete mold filling, then filling volume increases, but excess material forms protrusions and shoulders on microlens edges

Engineering Contradiction:

Improvemelt filling volumeVSAvoidmicrolens contour accuracy

Core Design Contradiction:

Quantity of substanceVSShape

Solution Approach 1:

The patent replaces reliance on mechanical force (pressure) to fill the mold with a chemical approach using a release agent. This substitution allows the viscous melt to flow into the mold cavity more easily through reduced adhesion, achieving complete filling with the correct amount of material without forming excess protrusions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the mold cavity is designed with tight tolerances to ensure precise microlens formation, then manufacturing precision improves, but the high viscosity melt cannot adequately fill the cavity

Engineering Contradiction:

Improvemicrolens dimensional accuracyVSAvoidmold filling difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The release agent serves as a mediator that enables the viscous melt to flow into tightly toleranced mold cavities by reducing surface adhesion. This intermediary allows the melt to penetrate into precise, small-dimensional cavities that would otherwise be inaccessible to high-viscosity materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method effectively avoids the formation of excess material and misshaping, resulting in microlenses that provide a visually accurate and complete reproduction of objects, enhancing the optical effect in microlens arrays.

Implementation Method 1

The layer is cured by irradiation with UV radiation, i.e. the plastic or resin is polymerized.

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP4530055A1Method of forming an array of microlenses made of plastic or resin on an arcuate substrate

Publication Date: 2025.04.02 KOENIG & BAUER AG

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AI summary

The invention relates to a method for producing an arrangement of microlenses (01) made of a plastic or resin on an arc-shaped substrate (03), wherein a layer of liquid or plasticized plastic or resin is applied to at least one specimen of the substrate (03) in a screen printing process in a sheet-fed printing machine (11), then the arrangement of microlenses (01) to be produced is formed from the layer consisting of the plastic or resin in an embossing process using a forming tool (07), after which the layer formed into microlenses (01) on the respective specimen of the substrate (03) is hardened by irradiation with UV radiation, wherein a forming tool (07) is used.which, for forming each of the microlenses (01) to be produced in the arrangement with a lens width (L) of a maximum of 100 µm, has cavities forming shapes with a pair of concave or convex surfaces (02) opposite each other at a distance (a) in the transport direction (T) of the substrate (03) to be transported by the sheet-fed printing press (11) and/or transversely to the transport direction (T) of the substrate (03) to be transported by the sheet-fed printing press (11), wherein the distance (a) between the respective pair of opposing concave or convex surfaces (02) is at least 10% of the respective lens width (L).