Retroreflective Sheet with Concavo-Convex Colored Layer
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Solution Overview
Problem
Conventional retroreflective sheets have a step between reflective and non-reflective regions, leading to delamination issues and a complex manufacturing process due to the formation of light reflective members only in reflective regions, which complicates attachment and increases the risk of delamination.
Innovation Solution
A retroreflective sheet design where the colored layer is thicker in non-reflective regions, creating a concavo-convex surface, and the light concentrating and reflective layers are formed in the concave portions, eliminating the step between regions and enhancing adhesion, along with a method involving a mask tape to confine bead alignment and deposition of reflective layers without cutting, simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light reflective members are formed only in reflective regions, then the retroreflective function is achieved, but a step is created between reflective and non-reflective regions causing delamination
Solution Approach 1:
The patent applies local quality by making the colored layer thickness vary across different regions. Specifically, the colored layer is made thicker in non-reflective regions and thinner in reflective regions, allowing the light reflective members to be formed at different heights without creating surface steps. This local variation in layer thickness enables both regions to have their light reflective members at the same elevation, eliminating the delamination problem caused by surface irregularities.
2Manufacturing precision
If light reflective members are formed only in reflective regions, then the retroreflective pattern is achieved, but the manufacturing process becomes complex due to selective formation requirements
Solution Approach 1:
The patent segments the colored layer into two distinct thickness regions: a first colored layer in reflective regions and a second colored layer in non-reflective regions. This segmentation allows each region to be processed independently with optimized parameters. The first colored layer is formed with a first thickness suitable for reflective regions, while the second colored layer is formed with a greater second thickness for non-reflective regions, enabling simplified manufacturing without compromising pattern accuracy.
Solution Approach 2:
The patent applies preliminary action by pre-forming the colored layer with varying thickness before depositing the light reflective members. The colored layer is prepared in advance with a thickness profile that anticipates the subsequent formation of light reflective members in both reflective and non-reflective regions. This preliminary thickness variation ensures that when light reflective members are formed in both regions, they end up at the same surface level, eliminating the need for complex post-processing steps.
3Ease of manufacture
If the colored layer has uniform thickness, then the manufacturing process is simpler, but a step is created between reflective and non-reflective regions leading to delamination
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through spatially varying colored layer thickness. Instead of using a uniform thickness that causes delamination, the colored layer is made thicker in non-reflective regions and thinner in reflective regions. This local variation maintains manufacturing simplicity while ensuring that light reflective members formed in both regions are at the same height, thereby preventing delamination and improving attachment stability.
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
Prevents delamination of the light reflective member from the base and simplifies the manufacturing process by eliminating the step between reflective and non-reflective regions, ensuring stable attachment and improved visibility in low-light conditions.
Implementation Method 1
a reflective layer formed in a concave portion of the reflective region on the surface of the colored layer
Implementation Method 2
a light concentrating layer having a plurality of beads aligned therein on the reflective layer
Implementation Method 3
the light concentrating layer 21 concentrates incident light and the reflective layer 17 reflects concentrated light
Data Source
AI summary
A retroreflective sheet and a fabrication method thereof are provided, the retroreflective sheet including a base, a bonding layer formed on the base, a colored layer formed to be thicker in a non-reflective region NRA2 than in a reflective region RA2 to have a concavo-convex surface on the bonding layer, and having a fluorescent function or a phosphorescent function or having the both fluorescent and phosphorescent functions, a reflective layer formed in the concave portion of the reflective region RA2 on the surface of the colored layer, and a light concentrating layer having a plurality of beads aligned therein on the reflective layer. Thus, since a step is not generated between the reflective region and the non-reflective region, the light reflective member can be prevented from being delaminated from the body when used, and also, the light reflective member can be simply formed in the reflective region of the colored layer.