Retro-reflective Sheet Light Transmission for Colored Area Brightness
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Solution Overview
Problem
Retro-reflective sheets have limited light reflection efficiency on colored areas, resulting in decreased visibility at night, with the related art reflecting approximately 30 cd/lux*m2 on colored areas compared to 500 cd/lux*m2 on reflective areas, leading to overall reduced visibility when both areas have the same width.
Innovation Solution
A retro-reflective sheet design incorporating a light transmitting layer that scatters and emits light through a first light condensing layer, combined with a reflective part formed by thermal pressing on a reflective area, enhances light reflection on colored areas by transmitting and scattering light input, increasing the light emitted through the colored layer to approximately 200-400 cd/lux*m2, and maintaining high reflection on reflective areas at 500 cd/lux*m2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional retro-reflective sheet structure is used with a colored layer containing fluorescent or light accumulating pigments, then the colored area can emit light at night, but the light reflection efficiency on colored areas is limited to approximately 30 cd/lux*m2, resulting in decreased visibility
Solution Approach 1:
The patent applies composite materials by combining a light transmitting layer (transparent resin) with a colored layer containing fluorescent or light accumulating pigments. This composite structure allows the light transmitting layer to scatter and emit light while the colored layer provides fluorescence or light accumulation, achieving enhanced light reflection efficiency of 200-400 cd/lux*m2 on colored areas and significantly improving nighttime visibility
Solution Approach 2:
The patent changes the physical and optical parameters of the colored layer by incorporating fluorescent pigments and light accumulating pigments in specific proportions. This parameter change enables the colored layer to not only transmit light but also emit light through fluorescence and light accumulation, increasing the light reflection efficiency from the conventional 30 cd/lux*m2 to 200-400 cd/lux*m2
2Illumination intensity
If the widths of reflective areas and colored areas are made equal, then the sheet has a balanced stripe pattern, but the total light reflection is only approximately 265 cd/lux*m2 due to low reflection from colored areas
Solution Approach 1:
The patent uses composite materials in the colored layer to dramatically increase its light reflection efficiency from 30 cd/lux*m2 to 200-400 cd/lux*m2. This allows the stripe pattern to maintain symmetric widths while achieving a total light reflection of 350-450 cd/lux*m2, resolving the contradiction between pattern symmetry and total reflection intensity
3Device complexity
If only a colored layer with fluorescent pigments is used, then the structure is simple, but the light reflection efficiency remains low at approximately 30 cd/lux*m2
Solution Approach 1:
The patent creates a composite structure by adding a light transmitting layer above the colored layer. This simple two-layer composite design enables the light transmitting layer to scatter light in multiple directions while the colored layer emits light through fluorescence or light accumulation, achieving 200-400 cd/lux*m2 reflection efficiency without significantly increasing structural complexity
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 improved design significantly enhances visibility by increasing light reflection on colored areas to 200-400 cd/lux*m2, while maintaining high reflection on reflective areas, resulting in a total reflection of approximately 350-450 cd/lux*m2 when both areas have equal widths, thereby improving nighttime visibility.
Implementation Method 1
configured to emit a portion of light obtained by scattering light that transmitted through the light transmitting layer on an interface with the colored layer
Implementation Method 2
together with the fluorescent or accumulated light of a colored layer
Implementation Method 3
emitting light that has been accumulated by absorbing light during the day
Implementation Method 4
configured to emit light input through a second light condensing layer to the outside
Implementation Method 5
first light condensing layer formed by scattering a plurality of beads on the colored layer
Data Source
AI summary
Disclosed are a retro-reflective sheet and a method for manufacturing the same. The retro-reflective sheet includes a heat-resistant film, a first thermoplastic bonding layer, a first heat-resistant layer, a colored layer, a light transmitting layer, a colored part allowing a portion of scattered light to be emitted to the outside through a first light condensing layer, a second thermoplastic bonding layer, a second heat-resistant layer, a reflective layer, and a reflective part reflecting light input to a reflective area through a second light condensing layer.