Quantization Phase Difference Structure for Holographic Security

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Solution Overview

Problem

Conventional holograms used for security features in securities and cards suffer from blurring, color instability, and reduced brightness, making them ineffective for forgery prevention, and ink solutions face challenges with color-shift and durability.

Innovation Solution

An optical structure with a quantization phase difference structure and multiple-diffraction regions that reflect light in a manner simulating a three-dimensional effect, providing a sparkling and blinking appearance without color-shift, and an ink with high durability and stable color.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional diffraction grating structure is used to create holographic security features, then color effects can be achieved, but color shift occurs due to viewing angle and the image becomes blurred

Engineering Contradiction:
Improvehologram manufacturingVSAvoidimage clarity and color stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the continuous diffraction grating structure into discrete dot arrays with specific pitch relationships. By dividing the holographic structure into multiple discrete diffraction regions with different spatial frequencies, the system achieves color stability while maintaining manufacturability through standardized dot pattern replication

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the fundamental parameters of the diffraction structure by using dot arrays with specific pitch ratios (e.g., 1:2, 1:3 relationships) rather than continuous gratings. This parameter change eliminates color shift by ensuring that diffraction orders from different regions overlap constructively only at the intended wavelength, while maintaining ease of manufacture through digital pattern generation

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If observation conditions are restricted to improve hologram quality, then image clarity improves, but it imposes a strain on the observer

Engineering Contradiction:
Improvehologram image qualityVSAvoidobserver convenience
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent creates a dynamic viewing experience where the holographic image automatically adapts to different viewing angles and lighting conditions. The dot array structure with specific pitch relationships ensures that the image remains clear and color-stable across a wide range of observation conditions, eliminating the need for observers to maintain specific viewing geometries

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The holographic structure is designed to function effectively under multiple viewing conditions and with different light sources. The dot array pattern with controlled pitch relationships creates an image that maintains its quality whether viewed from different angles, under different lighting intensities, or with various wavelength compositions, making it universally observable without strain

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If ink is used for authentication to provide durability and stable color, then color stability improves, but durability and resistance to fading remain insufficient

Engineering Contradiction:
Improvecolor stabilityVSAvoiddurability and fade resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent combines holographic optical elements with ink layers to create a composite authentication structure. The holographic component provides structural color stability that is inherently resistant to fading, while the ink layer adds chemical durability and tamper evidence. This composite approach achieves both color stability and reliability that neither material could provide alone

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 optical structure enhances visual quality and security by maintaining a three-dimensional effect regardless of the light source, while the ink ensures long-lasting, direction-independent color, improving the security features of securities and cards.

Implementation Method 1

An optical structure with a quantization phase difference structure and multiple-diffraction regions that reflect light in a manner simulating a three-dimensional effect

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The embossed surface has a multiple-diffraction region on a part or the entire surface. A quantization phase difference structure is formed on the multiple-diffraction region

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3660558B1Optical structure and authentication body
Publication Date: 2024.11.27 TOPPAN HOLDINGS INC
  • EP3660558B1 patent drawingFigure 1A~1B
  • EP3660558B1 patent drawingFigure 2~3
  • EP3660558B1 patent drawingFigure 4A~4C

AI summary

There is provided an optical structure having a quantization phase difference structure on one surface of a quantization phase difference structure layer, wherein in the quantization phase difference structure, a plurality of quantization projecting portions in a constant size and a plurality of quantization recessed portions in a constant size are aligned, wherein a multiple diffraction region has the quantization phase difference structure where ribbed projecting portions, in which the quantization projecting portions are aligned in one direction, are arranged adjacent to and alternately with groove-like recessed portions, in which the quantization recessed portions are aligned parallel to the ribbed projecting portions, and wherein the multiple diffraction region is a quantization phase difference structure configured to reproduce a plurality of reproduction points discrete in one direction and arranged regularly.