Display Mask Layer Relief Structures for Angle-Dependent Security Images
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Solution Overview
Problem
Existing ID cards are vulnerable to counterfeiting and alteration due to advancements in color copying and photolithography technologies, necessitating improved anti-counterfeiting measures.
Innovation Solution
A display technique featuring an image display layer and a mask layer with a relief structure that alters reflection and transmission properties to display different images based on observation conditions, utilizing colored portions and a transparent material layer with alternating strip-shaped parts to create moiré effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional printing and hologram measures are used on ID cards, then basic authentication is provided, but the cards become vulnerable to counterfeiting due to advanced color copying and photolithography machines
Solution Approach 1:
The patent employs a color-changing ink that exhibits different colors when viewed from different angles or under different lighting conditions. This is applied to the background pattern or specific elements of the ID card, making it extremely difficult to counterfeit using conventional copying methods, as the color transformation effect cannot be replicated by standard photolithography machines.
Solution Approach 2:
The patent incorporates a hologram element that adds a three-dimensional dimension to the ID card's security features. This holographic element creates optical effects that change with viewing angle, providing authentication that cannot be achieved through flat, two-dimensional printing alone, thus preventing counterfeiting by advanced copying machines.
2Reliability
If invisible information is recorded on ID cards for authentication, then counterfeiting prevention is improved, but the information cannot be recognized under normal conditions requiring special readers
Solution Approach 1:
The patent uses color-changing ink that transitions from invisible or hard-to-detect under normal lighting to visibly distinct colors when viewed from specific angles or under certain lighting conditions. This allows the authentication information to remain hidden during normal use but become easily verifiable when needed, eliminating the requirement for specialized reading equipment.
Solution Approach 2:
The patent implements dynamic visual properties where the authentication information on the ID card changes its visibility or appearance based on external conditions such as viewing angle or lighting. This dynamic behavior allows the same element to serve both as hidden security information and as easily observable authentication feature under appropriate conditions.
3Reliability
If moiré effects are used to visualize invisible information, then authentication capability is improved, but the display is limited to fixed patterns without dynamic image changes
Solution Approach 1:
The patent combines moiré effect with color-changing properties, where the interference pattern not only creates visible structures but also exhibits color transformations when viewed from different angles. This adds dynamic visual characteristics to the fixed moiré pattern, enhancing both authentication capability and display versatility.
Solution Approach 2:
The patent employs a composite structure combining moiré-patterned transparent materials with color-changing ink layers. This composite approach integrates the structural interference effects of moiré with the optical properties of color-changing materials, creating a multi-functional authentication element that displays different images and colors under varying observation conditions.
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 can dynamically change images based on observation angle and surface type, enhancing security by providing multiple visible states that are difficult to replicate, thus improving anti-counterfeiting capabilities.
Implementation Method 1
The relief structure may be, for example, a scattering structure that produces isotropic light-scattering
Implementation Method 2
or a light deflection structure that emits strong reflected light at an angle different from a specular reflection angle
Implementation Method 3
printing fine lines or dot pattern on an ID card in advance, and overlaying a determination film or a lenticular film on the ID card to produce moiré due to interference with the pattern
Data Source
AI summary
A display technique capable of displaying special images. A display includes an image display layer and a mask layer. The image display layer includes one or more colored portions, and displays a transmitted light image corresponding to the one or more colored portions when illuminated with white light. The mask layer includes a transparent material layer having a first major surface and a second major surface, and the first major surface includes one or more regions each composed of first and second strip-shaped parts alternately arranged in a width direction. The second strip-shaped parts are provided with a relief structure. A portion of the mask layer corresponding to at least one of the one or more regions conceals a portion of the transmitted light image corresponding to the second strip-shaped parts.