Counterfeit Prevention Structure with Selective Reflective Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing counterfeit prevention structures face challenges in achieving precise positional accuracy and high productivity while maintaining low manufacturing costs, particularly in forming reflective layers on complex optical elements like diffraction gratings and holograms.
Innovation Solution
A counterfeit prevention structure is created using a fine-relief-formation layer with distinct areas of varying depth-to-width ratios, where fine particles are filled in recesses of one area and a reflective layer is applied only to another area, allowing for precise etching and high positional accuracy, and a manufacturing method involving dry-coating and etching ensures the reflective layer is selectively formed on specific areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photolithography method is used to provide reflective layer on diffraction grating, then high definition reflective layer can be provided at high speed, but misalignment of not less than 100 μm occurs due to difficulty in strict positioning of mask relative to relief configuration
Solution Approach 1:
The relief configuration itself serves as the positioning reference for the reflective layer formation. The mask is designed to align with the relief pattern, allowing the structure to self-position without requiring external high-precision alignment equipment or complex positioning procedures.
Solution Approach 2:
The relief configuration is formed first as a preliminary structure that will subsequently guide the reflective layer formation. This preliminary structure serves as a built-in alignment reference that simplifies the subsequent reflective layer deposition process.
2Manufacturing precision
If etching is performed to leave reflective layer only on high depth-to-width ratio area, then selective reflective layer formation is achieved, but the conditions are quite limited and the reflective layer becomes thin with varied reflectance
Solution Approach 1:
The patent modifies the depth-to-width ratio parameter of the relief configuration to create distinct areas with different etching characteristics. By controlling the geometry parameters of the relief structure, selective etching is achieved while maintaining adequate reflective layer thickness and consistent reflectance across the surface.
3Manufacturing precision
If large difference in depth-to-width ratio is provided between areas to ensure etching speed difference, then selective etching is improved, but the structure becomes finer and more complicated which is difficult to mold
Solution Approach 1:
The patent applies local quality by creating specific geometric characteristics in specific areas of the relief configuration. Certain regions are designed with particular depth-to-width ratios that differ from other regions, allowing selective etching to occur in specific locations while maintaining overall structural simplicity and moldability.
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
This approach enables the formation of a reflective layer with high positional accuracy, making the counterfeit prevention structure difficult to counterfeit and reduces manufacturing costs while maintaining high productivity.
Implementation Method 1
a metal reflective layer is provided, by means of a vacuum vapor deposition method, to a structure
Implementation Method 2
optimizing etching conditions to thereby ensure a difference in the etching speed between the areas
Data Source
Figure 1~2
Figure 3(a)~4
Figure 5(a)~6
AI summary
A counterfeit prevention structure (10) includes a fine-relief-formation layer (11) which is provided with a first area (13) having an optical element that includes a relief structure whose depth-to-width ratio that is a ratio of a depth relative to a width is not less than a first value, and a second area (14) having an optical element that includes a relief structure whose depth-to-width ratio is less than the first value. The counterfeit prevention structure (10) further includes a reflective layer (12) that is arranged on the relief structure included in the area having the lower light transmittance among the first and second areas (13;14).