Dual-Sided Security Element Using Reflective Micro-Imaging

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Solution Overview

Problem

Existing security elements that depict microstructure objects on both sides are thick due to the need for microlenses on both sides, making them bulky and difficult to produce efficiently.

Innovation Solution

A security element with reflective micro-imaging elements on one side and micro-lenses on the other, where both elements can share the same focal plane, allowing for a compact design and simultaneous production of microstructure objects on both sides, reducing overall thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If microlenses are used on both sides to depict microstructure objects on both sides, then the security element can be viewed from both sides, but the overall thickness becomes very large

Engineering Contradiction:
Improveviewability from both sidesVSAvoidoverall thickness
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent divides the imaging elements into two distinct types: reflective micro-imaging elements on the front side and transmissive microlenses on the back side. This segmentation allows each type to be optimized for its specific function, with reflective elements providing shorter focal length and reduced thickness contribution, while microlenses maintain effective imaging capability from the rear.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using the conventional approach of placing identical microlenses on both sides, the patent inverts the design by using reflective micro-imaging elements on the front side. This inversion leverages the optical principle that reflective elements can achieve the same imaging function with a shorter optical path, thereby reducing the overall thickness of the security element.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If microlenses are used on both sides, then microstructure objects can be displayed on both sides, but production becomes more complex and less efficient

Engineering Contradiction:
Improvedual-sided microstructure displayVSAvoidproduction complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines the formation of front-side and back-side microstructure objects into a single embossing step. The embossing tool simultaneously creates both microstructure patterns on the security element, eliminating the need for separate embossing operations and significantly simplifying the production process.

Inventive Principle:
Principle #5Merging (Combining)

3Length of stationary object

If reflective micro-imaging elements are used, then the focal length can be reduced, but the device complexity increases

Engineering Contradiction:
Improvefocal lengthVSAvoidimaging element complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent employs a single embossing tool that serves multiple functions: it creates both the front-side reflective micro-imaging elements and the back-side transmissive microlenses, and simultaneously forms both microstructure objects. This multi-functionality reduces device complexity despite the advanced optical design, as one tool performs what would otherwise require multiple specialized processes.

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

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 results in a thinner security element that maintains the ability to display different microstructure objects from both sides, enhancing authenticity verification while simplifying production processes.

Implementation Method 1

a plurality of reflective first micro-imaging elements arranged areally in a first pattern

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the first microstructure object is imaged in front of the upper side enlarged by means of the first micro-imaging elements

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

second micro-imaging elements arranged areally in a second pattern, and a second microstructure object

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

the second microstructure object is imaged enlarged in front of the underside by means of the second micro-imaging elements

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP2435254B1Security element, security system, and production method therefor
Publication Date: 2015.07.08 GIESECKEDEVRIENT IP
  • EP2435254B1 patent drawingFigure 1~2
  • EP2435254B1 patent drawingFigure 3~5
  • EP2435254B1 patent drawingFigure 6~7

AI summary

The invention relates to a security element for security documents, valuable documents or the like, comprising a carrier (3) having an upper (4) and a lower side (7), said carrier comprising several reflective first micro-imaging elements (8) arranged flatly in a first pattern, and comprising second micro-imaging elements (9) arranged flatly in a second pattern; comprising a first micro-structure object (M1) having several first micro structures (5) arranged in the first micro-structure pattern adapted to the first pattern such that an enlarged image of the first micro-structure object (M1) is generated in front of the upper side (4) by the first micro-imaging elements (8); comprising a second micro-structure object (M2) having several second micro structures (6) arranged in a second micro-structure pattern adapted to the second pattern so that an enlarged image of the second micro-structure object (M2) is generated in front of the lower side (7) by the second micro-imaging elements (9).