Patterned Wavelength-Selective Film for Retroreflective Substrates
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Solution Overview
Problem
Existing methods face challenges in applying unique patterned embedded images on substrates using wavelength-selective films, particularly on retroreflective films, as they are difficult to detect in both daytime and nighttime conditions due to reflection, absorption, or scattering properties.
Innovation Solution
A cost-effective method involving a patterned wavelength-selective film is applied to a substrate using a structurally weak film with adhesive, where portions break to remain in contact with the adhesive, forming a patterned film that can be detected under specific lighting conditions, and optionally includes a protective layer and encapsulation adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wavelength-selective film is applied to retroreflective substrate, then detection capability in both daytime and nighttime is improved, but application difficulty and pattern uniqueness are worsened
Solution Approach 1:
The adhesive is applied in a predetermined pattern before the wavelength-selective film is placed on the substrate. This preliminary patterning of the adhesive layer guides where the film will break and remain attached, enabling unique pattern formation without requiring complex post-application manipulation or precise real-time alignment during the lamination process.
2Manufacturing precision
If adhesive is applied in pattern, then patterned film formation is improved, but manufacturing complexity is worsened
Solution Approach 1:
The adhesive layer serves as an intermediary element between the substrate and the wavelength-selective film. By patterning the adhesive layer, it acts as a mediator that controls the final pattern formation through selective bonding, simplifying the overall manufacturing process compared to direct film patterning methods.
3Manufacturing precision
If structurally weak film is used, then pattern transfer to adhesive is improved, but film strength is worsened
Solution Approach 1:
The mechanical properties of the wavelength-selective film are modified by changing its structural parameters - specifically making it structurally weak through design choices such as thinning the film or incorporating weak points. This parameter change enables the film to break and transfer its pattern to the adhesive layer during application, while the film still maintains sufficient strength for handling and application processes.
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 method allows for high-contrast detection of patterned images in both daytime and nighttime conditions, enhancing visibility and usability of the patterned wavelength-selective film on retroreflective substrates.
Implementation Method 1
Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength and therefore can provide high-contrast against a background
Implementation Method 2
Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength
Implementation Method 3
Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength
Implementation Method 4
Retroreflective elements reflect incident light back towards the direction of the light source
Implementation Method 5
applying adhesive in a pattern between the substrate and the wavelength-selective film, breaking portions of the wavelength-selective film at the adhesive to form patterned portions
Data Source
AI summary
The disclosed patterned wavelength-selective material and process for making the patterned wavelength-selective material uses patterned applied adhesive and a structurally weak wavelength-selective material that includes portions that contact the adhesive and break to remain in contact with the adhesive. In one embodiment, the wavelength-selective material comprises an array of sections with cuts at least partially through a wavelength-selective film at each section secured to the adhesive. In another embodiment, the wavelength-selective film comprises a transfer stack of layers.