Retroreflective Pavement Markers with Embedded Microspheres

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Solution Overview

Problem

Pavement markings face durability and retention issues due to detachment of the binder and retroreflective layer from the interface, and reduced efficiency from cracks in glass beads under stress, making long-term durability challenging.

Innovation Solution

A retroreflective pavement marker design featuring a core with protrusions and cavities that house microsphere lenses, where an adhesive agent binds the lenses within the cavities, and a softening material fixes them, providing enhanced durability and resistance to stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If glass beads are used as retroreflective elements, then retroreflective performance is improved, but cracks occur in the glass beads under stress reducing efficiency

Engineering Contradiction:
Improveretroreflective performanceVSAvoidcrack resistance under stress
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a core material (such as rubber or plastic) combined with embedded optical elements (glass beads or prisms). This composite design allows the core to provide mechanical strength and stress resistance while the optical elements provide retroreflective performance, resolving the contradiction between retroreflective efficiency and crack resistance.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If binder and retroreflective layer are used together, then retroreflective function is achieved, but detachment occurs at the interface reducing durability

Engineering Contradiction:
Improveretroreflective functionVSAvoidinterface bonding stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent merges the binder and retroreflective layer into an integrated structure where optical elements are directly embedded in the core material. This eliminates the separate retroreflective layer and its interface with the binder, preventing detachment while maintaining retroreflective function through the embedded optical elements.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If pavement marker is designed for durability, then resistance to wear and elements is improved, but complexity of structure increases

Engineering Contradiction:
Improvedurability against wear and elementsVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite materials where a durable core material (rubber or plastic) provides resistance to wear and environmental elements, while embedded optical elements provide retroreflective functionality. This composite approach achieves durability without excessive structural complexity by integrating multiple functions into a unified structure.

Inventive Principle:
Principle #40Composite materials

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 design significantly improves the durability and retention of retroreflective performance over time, withstanding stress and environmental conditions without significant loss of reflectivity, as demonstrated by durability tests.

Implementation Method 1

the cavity includes an adhesive agent that binds at least two microsphere lenses in the cavity

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the microsphere lenses are fixed within the cavity by a softening material included in the core

Methodology Applied
Scientific EffectSoftening: Melting

Data Source

PatentEP2758815B1Retroreflective elements
Publication Date: 2016.10.26 3M INNOVATIVE PROPERTIES CO
  • EP2758815B1 patent drawingFigure 1A~1B
  • EP2758815B1 patent drawingFigure 2
  • EP2758815B1 patent drawingFigure 3A~3B

AI summary

The present application relates to a pavement marker including a core from which extends protrusions and a cavity between adjacent protrusions. The microsphere lenses are fixed within the cavity by one of a softening material disposed in the core and an adhesive agent disposed in the cavity.