Light-Scattering Display with Anisotropic Relief Patterns for Forgery Prevention

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Solution Overview

Problem

Existing light-scattering displays for forgery prevention lack sufficient differentiation in light-scattering patterns, leading to inadequate forgery-prevention effects due to limitations in controlling the density and shape of recesses and protrusions, especially in fine regions.

Innovation Solution

A display featuring first light-scattering regions with linear protrusions or recesses having different longitudinal directions and random intervals, combined with second light-scattering regions having non-linear shapes, enhancing the anisotropic light-scattering ability and providing a high forgery-prevention effect by varying brightness and visibility based on observation angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If etching or chemical methods are used to form relief patterns, then the manufacturing process is simple, but the density of recesses and protrusions cannot be differentiated in fine regions

Engineering Contradiction:
Improveease of forming relief patternVSAvoiddensity control in fine regions
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical/chemical etching methods with EB (electron beam) writing technology to form relief patterns. This substitution enables precise control of recess and protrusion densities in fine regions while maintaining ease of manufacture, as EB writing allows arbitrary patterning without the limitations of conventional etching or chemical methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a relief-type diffraction grating is used, then the manufacturing is easy with laser facilities, but the light-scattering visual effect is insufficient for forgery prevention

Engineering Contradiction:
Improveease of forming diffraction gratingVSAvoidforgery-prevention effect
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges a relief-type diffraction grating with light-scattering patterns featuring random intervals of recesses and protrusions into a single integrated display structure. This combination maintains the ease of manufacture of diffraction gratings while adding the light-scattering visual effect necessary for robust forgery prevention, as the random interval pattern cannot be replicated by conventional copying methods.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite optical structure combining diffraction grating elements with light-scattering particles or structures. This composite approach leverages both the ease of diffraction grating fabrication and the enhanced visual effects of light scattering, achieving superior forgery prevention capability that neither component could provide alone.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If light-scattering patterns with regular intervals are used, then the manufacturing is straightforward, but the anisotropic light-scattering ability is insufficient

Engineering Contradiction:
Improveease of forming light-scattering patternVSAvoidanisotropic light-scattering ability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces asymmetry by randomizing the intervals between recesses and protrusions in the light-scattering pattern. This asymmetric arrangement creates strong anisotropic light-scattering ability, where the scattering characteristics differ significantly depending on the observation angle, while remaining manufacturable through EB writing technology that can accommodate irregular patterns.

Inventive Principle:
Principle #4Asymmetry

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 display achieves a significant forgery-prevention effect by ensuring that images displayed on different regions can be observed distinctly under different conditions, making it difficult to replicate or forge, suitable for applications in securities and brand-name products.

Implementation Method 1

a display which displays an image by utilizing light-scattering

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

directions of the linear protrusions and/or recesses of the respective light-scattering regions are different from each other

Methodology Applied
Scientific EffectAnisotropic scattering: Scattering

Data Source

PatentEP3040747B1Display and labeled article
Publication Date: 2022.06.22 TOPPAN HOLDINGS INC
  • EP3040747B1 patent drawingFigure 1~2
  • EP3040747B1 patent drawingFigure 3~4
  • EP3040747B1 patent drawingFigure 5~6

AI summary

In accordance with one or more embodiments of the invention, there is provided a display comprising first light-scattering regions each provided with linear protrusions and/or recesses having the same longitudinal direction, the light-scattering regions being different from each other in the longitudinal direction, and a second light scattering region provided with protrusions and/or recesses each having a shape other than a linear shape.