Identity Document Hinge Composite Structure
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Solution Overview
Problem
Existing identity document hinges are either too flexible and fail to maintain a closed state or too rigid, failing to provide adequate resistance and flexibility.
Innovation Solution
A method involving a heat-fusible layer interposed between two woven layers, subjected to a rolling process to embed the hot melt layer within the woven meshes, using a polycarbonate thermofusible layer and woven layers with specific dimensions and thicknesses to achieve a balance between resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a hinge is made with a single woven layer or simple structure, then the manufacturing process is simplified, but the hinge becomes too flexible and cannot maintain a closed state
Solution Approach 1:
The hinge is constructed as a composite structure with three distinct layers: a first woven layer, a second woven layer, and a thermoplastic layer positioned between them. This composite configuration provides both structural integrity and flexibility, allowing the hinge to maintain a closed state while remaining manufacturable. The thermoplastic layer acts as an adhesive and structural connector between the woven layers, creating a balanced mechanical properties profile.
2Strength
If a hinge is made with multiple rigid layers, then resistance and strength are improved, but the hinge becomes too rigid and cannot allow the identity document to maintain a closed state
Solution Approach 1:
The invention carefully controls the parameters of the hinge components, specifically the mesh size of the woven layers (between 0.23 and 0.26 mm) and the thickness of the thermoplastic layer (between 40 and 60 μm). These parameter optimizations ensure the hinge has sufficient resistance while maintaining the flexibility needed to retain a closed state. The specific mesh dimensions and layer thicknesses create an optimal balance between rigidity and flexibility.
3Ease of operation
If the mesh size of woven layers is reduced, then the hinge becomes more flexible, but the resistance and structural integrity are compromised
Solution Approach 1:
The invention specifies a precise range for the mesh size parameter (0.23 to 0.26 mm) to achieve the optimal balance between flexibility and resistance. This parameter optimization ensures that the hinge remains flexible enough for operation while maintaining sufficient structural integrity. The thermoplastic layer thickness (40-60 μm) is coordinated with the mesh size to provide additional structural support without compromising flexibility.
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 provides a hinge with satisfactory resistance and flexibility, allowing the identity document to maintain a closed state effectively.
Implementation Method 1
the thermofusible layer and the woven layers are subjected to at least one rolling step at a rolling temperature so that the hot melt layer is embedded in the meshes of the woven layers
Implementation Method 2
the hot melt layer being made of a first material that is deformable and/or fusible at the lamination temperature
Data Source
Figure 1~3
Figure 4~6
AI summary
The invention relates to a method for producing an information sheet (18) of an identity document. According to the invention, the hinge (24) of the information sheet (18) is obtained by assembling by lamination a hot-melt layer (38) and two woven layers (40, 42) disposed on either side of the hot-melt layer (38), this latter being embedded in the mesh of the woven layers (40, 42) after laminating, the woven layers (40, 42) and/or the hot-melt layer (38) having features making it possible to obtain a compromise between a satisfactory strength for the hinge (24) and a flexibility for the hinge (24) allowing an identity document incorporating it to maintain a closed state. The invention also relates to an information sheet (18) obtained by said method and an identity document (10) comprising at least one such information sheet (18).