Transfer Film with Complementary Relief Structure for Optical Clarity

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Solution Overview

Problem

Existing transfer films, particularly hot stamping films, face challenges in mass production and surface protection due to limitations in nanoparticle application methods and toxicity concerns, while also struggling to form structural layers with precise microstructures for optical and tactile effects without causing imaging errors or mechanical instability.

Innovation Solution

A transfer film comprising a carrier film with a removable structural layer featuring a complementary microstructure, applied using a roll-to-roll process, which ensures mechanical stability and protection while allowing for thin, transparent layers that can be designed for anti-reflective, dirt-repellent, or diffuser effects, and can be integrated into optical systems without imaging errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a carrier film with master relief structure is used to transfer thin structural layers, then the structural layer thickness can be reduced and imaging errors are avoided, but the mechanical stability and protection of the surface structure during application are compromised

Engineering Contradiction:
Improveimaging precisionVSAvoidmechanical stability
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The system is divided into three functional segments: the carrier film with master relief structure that provides imaging precision, the transfer layer with complementary relief structure that forms the protective surface, and the adhesive layer that bonds them. This segmentation allows each component to specialize - the carrier film ensures precision while the transfer layer provides mechanical strength

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transfer layer acts as an intermediary between the carrier film and the final application surface. It receives the precise relief structure from the carrier film through the transfer process, then provides the mechanical strength and durability needed for the protective coating, while the adhesive layer serves as the bonding intermediary

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If nanoparticles are applied using spray gun coating process, then the surface can be protected, but the coating result depends on nanoparticle nature and application process, nanoparticles can detach during use, and toxicological effects are uncertain

Engineering Contradiction:
Improvesurface protectionVSAvoidproduction reliability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of directly applying nanoparticles to the surface, the invention creates a master relief structure on the carrier film and then transfers a complementary relief structure to form the protective layer. This copying approach ensures consistent, reproducible results that are independent of nanoparticle variations or spray application parameters

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention changes the fundamental parameter of how the protective layer is formed - from stochastic nanoparticle deposition via spray to deterministic relief structure transfer via embossing and adhesive bonding. This parameter change eliminates the variability and detachment issues associated with nanoparticle spray applications

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If structural layer is made transparent with thin thickness, then optical clarity is improved, but the layer becomes mechanically unstable and difficult to apply

Engineering Contradiction:
Improveoptical clarityVSAvoidmechanical stability
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The mechanical stability function is extracted from the transparent structural layer itself and assigned to the carrier film with master relief structure. This allows the structural layer to be made as thin as needed for optical clarity while the carrier film provides the necessary mechanical support during handling and application

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system forms a composite structure where the thin transparent structural layer is bonded to the mechanically robust carrier film. This composite approach combines the optical properties of the thin layer with the mechanical properties of the carrier film, achieving both optical clarity and mechanical stability

Inventive Principle:
Principle #40Composite materials

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

The solution enables the cost-effective mass production of multi-layer bodies with precise structural layers that provide technical surface protection, reduce reflections, and repel dirt, while maintaining optical clarity and mechanical stability, thus enhancing the functionality of surfaces in displays and optical components.

Implementation Method 1

a master relief structure is molded into the carrier film, the structural layer is applied, a relief structure complementary to the master relief structure of the carrier film being molded into the structural layer

Methodology Applied
Scientific EffectMaterial transfer:

Implementation Method 2

the complementary relief structure being fixed by solidifying or hardening the structural layer

Methodology Applied
Scientific EffectSolidifying or hardening:

Implementation Method 3

The carrier film with the master relief structure ensures sufficient mechanical stability and protection of the surface structure when applying the transfer layer to a surface to be protected

Methodology Applied
Scientific EffectMechanical stability:

Implementation Method 4

designed for anti-reflective, dirt-repellent, or diffuser effects

Methodology Applied
Scientific EffectAnti-reflective effect: Anti-Reflective Coating

Implementation Method 5

designed for anti-reflective, dirt-repellent, or diffuser effects

Methodology Applied
Scientific EffectDirt-repellent effect: Hydrophobe

Implementation Method 6

designed for anti-reflective, dirt-repellent, or diffuser effects

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP1871620B1Transfer film
Publication Date: 2011.08.03 OVD KINEGRAM AG
  • EP1871620B1 patent drawingFigure 1
  • EP1871620B1 patent drawingFigure 2a~2d
  • EP1871620B1 patent drawingFigure 3~4

AI summary

The invention relates to a transfer film, in particular a hot embossing film, comprising a support film (18) and a transfer layer with a structured surface (14) that is applied to the support film (18) and can be detached from the latter (18). According to the invention, the support film (18) comprises a master relief structure (18m) on the side facing the structured layer (14) and the latter (14) comprises a relief structure (14o) that complements the master relief structure of the support film (18) on the side facing said film (18). The invention also relates to a method for producing the transfer film and to a multi-layered body (1) that is formed using said structured layer (14), the latter having a thickness of <100 μm.